William Killgore

Interests

Research

Sleep; Sleep Deprivation; Neuroimaging; Post-traumatic Stress Disorder (PTSD); Mild Traumatic Brain Injury (mTBI); Depression; Human Performance; Emotion; Emotional Intelligence; Risk Taking; Decision Making; Stimulant Countermeasures; Caffeine

Courses

Scholarly Contributions

Chapters

• Satterfield, B. C., & Killgore, W. D. (2019). Sleep loss, executive function, and decision-making. In Sleep and Health. Academic Press. doi:10.1016/B978-0-12-815373-4.00026-5
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  Abstract Sleep loss is common in today’s society, and while most individuals have experienced sleep loss, few recognize the negative consequences sleep loss has on cognitive functioning. There is a general consensus that sleep loss results in decreased attention, vigilance, and alertness. While some believe that impaired vigilant attention is the underlying cause of performance decrement across all domains, new evidence suggests that this may not actually be the case. In fact, sleep loss does not appear to affect cognitive processes in a global manner. Rather, insufficient sleep differentially impacts various components of cognitive functioning. In this chapter, we will discuss how sleep loss impacts a variety of cognitive domains, including vigilant attention, working memory, inhibitory control, cognitive control, problem solving, risk-taking, judgment, and decision-making. In doing so, we will also discuss the common tasks used to test these specific domains and the neural mechanisms thought to mediate task-specific performance.
• Satterfield, B. C., Raikes, A. C., & Killgore, W. D. (2019). Sleep in Social Cognition and Judgment. In Sleep, Personality, and Social Behavior. Springer, Cham. doi:10.1007/978-3-030-30628-1_4
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  To successfully navigate the social world, individuals must be able to employ appropriate social cognitive processes to guide behaviors. This includes the ability to perceive and comprehend the behaviors and social dispositions of oneself and that of others, and place these perceptions into the context of one’s own interpersonal norms before a behavior can be enacted. Due to its complexity, social functioning is mediated by a number of factors, including sleep quantity and quality. Our society is currently facing a sleep loss epidemic, and unfortunately such frequent and cumulative sleep loss can have drastic consequences on an individual’s social functioning. Sleep loss impairs decision-making, self-regulation, and emotional processing - all of which impact social cognitive processes. This chapter provides a concise overview of the available literature assessing sleep loss in the context of social cognition and judgment. Sleep loss has been shown to unmask biases, prejudices, and ethical behavior. In addition, sleep loss significantly impacts social decision-making and prosocial behaviors such as trust, bargaining, altruism, and general team dynamics. Research efforts in these areas should utilize naturalistic testing paradigms and sleep schedules to gain a more comprehensive understanding of the intricate relationship between sleep and social cognition.
• Killgore, W. D. (2017). Socio-emotional and neurocognitive effects of sleep loss. In The Handbook of Operator Fatigue. CRC Press. doi:10.1201/9781315557366-15
• Klimova, A., Singh, P., & Killgore, W. D. (2017). White Matter Abnormalities in MS: Advances in Diffusion Tensor Imaging/Tractography. In Nutrition and Lifestyle in Neurological Autoimmune Diseases: Multiple Sclerosis. Academic Press. doi:10.1016/B978-0-12-805298-3.00003-7
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  Multiple sclerosis (MS) is a chronic debilitating disorder affecting the central nervous system (CNS), particularly the white matter. Over the years, there have been significant advances made in the management of MS including diagnosis and treatment. Magnetic resonance imaging (MRI) is one if the neuroimaging modalities which has revolutionized the diagnosis and early detection of the disease. MRI has also proven useful to monitor disease progression in patients with MS and estimate its prognosis. In this chapter we have described the neuroimaging findings in MS using various methods of MRI. On the basis of sequence and imaging parameters applied, MRI scans can provide T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (MRS) images, all of which may have applicability in the evaluation of patients with MS. Some of these sequences, especially DTI and MRS, have proven particularly helpful in understanding the pathology of this disease from a new perspective. We focus extensively on the recent development and application of DTI and fiber tractography in understanding and characterizing the white matter lesions that occur in MS. The application of these methods holds considerable promise for advancing our understanding of MS.
• Killgore, W. D. (2015). Sleep Deprivation and Behavioral Risk-Taking. In Modulation s of Sleep by Obesity, Diabetes, Age, and Diet. Academic Press. doi:10.1016/B978-0-12-420168-2.00030-2
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  Sleep deprivation temporarily alters brain functioning, particularly within the prefrontal cortex, the region most involved in regulating and modulating behavior. Some of these changes may affect cognitive processes that increase the propensity to engage in risk-taking behavior. Risk-taking can result from alterations in elementary cognitive functions, such as simple attention and lack of awareness of deficits, induced by sleep loss. Sleep loss can also increase risk-taking by reducing inhibitory capacity or by changing subjective willingness to engage in risk. At the highest levels, sleep loss can change behavioral, cognitive, and emotional factors that alter the willingness to take risks. Most research supports the hypothesis that sleep deprivation increases many aspects of risk-taking, including simple impairments in attention and judgment, greater willingness to accept risk, and a tendency to focus on short-term rather than long-term consequences, but it may also reduce the effort that individuals are willing to devote toward risky behavior.
• Killgore, W. D., & Weber, M. (2014). Sleep Loss and Performance. In Sleep deprivation and disease: Effects on the body, brain and behavior (pp. 209–229). Oxford University Press. doi:10.1093/MED:PSYCH/9780199928262.003.0049
• Killgore, W. D., & Weber, M. (2014). Sleep deprivation and cognitive performance. In Sleep Deprivation and Disease(pp 209--229). Springer New York.
• Killgore, W. D. (2011). Sleepiness: Caffeine and other alerting agents. In Sleepiness. Cambridge University Press. doi:10.1017/CBO9780511762697.040

Journals/Publications

• Arizmendi, B. J., Seeley, S. H., Allen, J. J., Killgore, W. D., Andrews-Hanna, J., Weihs, K., & O'Connor, M. F. (2023). A pull to be close: The differentiating effects of oxytocin and grief stimulus type on approach behavior in complicated grief. European journal of trauma & dissociation = Revue europeenne du trauma et de la dissociation, 7(3).
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  Theoretical models of complicated grief (CG) suggest that maladaptive motivational tendencies (e.g., perseverative proximity-seeking of the deceased; excessive avoidance of reminders) interfere with a person's ability to recover from their loved one's death. Due in part to conflicting evidence, little mechanistic understanding of how these behaviors develop in grief exists. We sought to (1) identify behavioral differences between CG and non-CG groups based on approach/avoidance bias for grief-, deceased-, and social-related stimuli, and (2) test the role of the neuropeptide oxytocin in shaping approach/avoidance bias. Widowed older adults with ( 17) and without ( 22) CG completed an approach/avoidance task measuring implicit bias for both personalized and non-specific grief-related stimuli (among other stimuli). In a double-blinded, randomized, counterbalanced design, each participant attended both an intranasal oxytocin session and a placebo session. Aims were to (1) identify differential effects of CG and stimulus type on implicit approach/avoidance bias [placebo session], and (2) investigate interactive effects of CG, stimulus type, and oxytocin vs. placebo on approach/avoidance bias [both sessions]. In the placebo session, participants in the non-CG group demonstrated an approach bias across all stimuli. Intranasal oxytocin had an overall slowing effect on the CG group's response times. Further, oxytocin decreased avoidance bias in response to photos of the deceased spouse in the CG group only. Findings support the hypothesis that oxytocin has a differential effect on motivational tendency in CG compared to non-CG, strengthening evidence for its role in CG. Findings also emphasize the need to consider differences in personalized vs. generic stimuli when designing grief-relevant tasks.
• Durham, M. R., Smith, R., Cloonan, S., Hildebrand, L. L., Woods-Lubert, R., Skalamera, J., Berryhill, S. M., Weihs, K. L., Lane, R. D., Allen, J. J., Dailey, N. S., Alkozei, A., Vanuk, J. R., & Killgore, W. D. (2023). Development and validation of an online emotional intelligence training program. Frontiers in psychology, 14, 1221817.
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  Emotional intelligence (EI) is associated with a range of positive health, wellbeing, and behavioral outcomes. The present article describes the development and validation of an online training program for increasing EI abilities in adults. The training program was based on theoretical models of emotional functioning and empirical literature on successful approaches for training socioemotional skills and resilience.
• Killgore, W. D., Jankowski, S., Henderson-Arredondo, K., Lucas, D. A., Patel, S. I., Hildebrand, L. L., Huskey, A., & Dailey, N. S. (2023). Functional connectivity of the default mode network predicts subsequent polysomnographically measured sleep in people with symptoms of insomnia. Neuroreport, 34(14), 734-740.
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  Insomnia is often accompanied by excessive pre-sleep rumination. Such ruminative thinking is also associated with increased connectivity of the default mode network (DMN). It is likely that DMN connectivity and associated rumination contribute to the pathogenesis of insomnia. We hypothesized that resting state functional connectivity (rsFC) between the DMN and other brain regions prior to bedtime would predict objectively measured sleep among individuals with insomnia. Twenty participants (12 female; M age = 26.9, SD = 6.6 years) with symptoms of insomnia underwent an rsFC scan in the early evening followed by a night of polysomographically (PSG) measured sleep. Connectivity of the DMN with other brain regions was regressed against several PSG sleep metrics, including time in wake, N1, N2, N3, REM, total sleep time (TST), and sleep efficiency (SE) at a cluster corrected false discovery rate (FDR) correction P < 0.05. The connectivity between DMN and cortical regions was negatively correlated with PSG indices of poorer sleep including time in wake (right angular gyrus) and N1 (precuneus) but positively correlated with time in REM (orbitofrontal cortex), TST (insula, orbitofrontal cortex, superior frontal gyrus, paracingulate gyrus), SE (orbitofrontal cortex). Connectivity between DMN and the pons was negatively correlated with SE. Among individuals with symptoms of insomnia, better sleep was predicted by rsFC between the DMN and cortical regions involved in executive functioning, consciousness, and complex cognition. Findings raise the possibility that future interventions aimed at suppressing pre-sleep DMN activation may weaken synergy between pre-sleep ruminative worry and complex cognitions, potentially ameliorating problems falling asleep.
• Smith, R., Persich, M. R., Chuning, A. E., Cloonan, S., Woods-Lubert, R., Skalamera, J., Berryhill, S. M., Weihs, K. L., Lane, R. D., Allen, J. J., Dailey, N. S., Alkozei, A., Vanuk, J. R., & Killgore, W. D. (2023). Improvements in mindfulness, interoceptive and emotional awareness, emotion regulation, and interpersonal emotion management following completion of an online emotional skills training program. Emotion (Washington, D.C.).
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  Socioemotional skills, such as the ability to recognize, understand, and regulate the emotions of self and others, are associated with both physical and emotional health. The present study tested the effectiveness of a recently validated online training program for increasing these emotional skills in adults. In this study, 448 participants (323 female) were randomly assigned to complete this training program or a placebo control program. Among those who completed the training program or placebo ( = 326), the training program led to improved scores post-training on measures of interoceptive and emotional awareness, mindfulness, emotion recognition, and emotion regulation strategies (e.g., reduced emotion suppression and greater impulse control) relative to placebo. In a smaller group of participants who also completed a 6-month follow-up visit ( = 94), sustained improvements were observed on several measures in those who completed the training program, while the placebo group instead showed decreased performance. This suggested a potentially protective effect against emotional challenges associated with the COVID-19 pandemic occurring during this time. These results suggest that this online training program shows promise in improving emotional skills relevant to adaptive social and emotional functioning, and that it might be useful as an intervention within at-risk populations and those with emotional disorders associated with reduced application of these skills. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
• Vital-Lopez, F. G., Doty, T. J., Anlap, I., Killgore, W. D., & Reifman, J. (2023). 2B-Alert App 2.0: personalized caffeine recommendations for optimal alertness. Sleep, 46(7).
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  If properly consumed, caffeine can safely and effectively mitigate the effects of sleep loss on alertness. However, there are no tools to determine the amount and time to consume caffeine to maximize its effectiveness. Here, we extended the capabilities of the 2B-Alert app, a unique smartphone application that learns an individual's trait-like response to sleep loss, to provide personalized caffeine recommendations to optimize alertness.
• Albertella, L., Kirkham, R., Adler, A. B., Crampton, J., Drummond, S. P., Fogarty, G. J., Gross, J. J., Zaichkowsky, L., Andersen, J. P., Bartone, P. T., Boga, D., Bond, J. W., Brunyé, T. T., Campbell, M. J., Ciobanu, L. G., Clark, S. R., Crane, M. F., Dietrich, A., Doty, T. J., , Driskell, J. E., et al. (2022). Building a transdisciplinary expert consensus on the cognitive drivers of performance under pressure: An international multi-panel Delphi study. Frontiers in psychology, 13, 1017675.
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  The ability to perform optimally under pressure is critical across many occupations, including the military, first responders, and competitive sport. Despite recognition that such performance depends on a range of cognitive factors, how common these factors are across performance domains remains unclear. The current study sought to integrate existing knowledge in the performance field in the form of a transdisciplinary expert consensus on the cognitive mechanisms that underlie performance under pressure.
• Dailey, N. S., Vanuk, J. R., Persich, M. R., Killgore, W. D., Grandner, M. A., & Cloonan, S. A. (2022). Sleep quality and duration are associated with greater trait emotional intelligence.. Sleep health, 8(2), 230-233. doi:10.1016/j.sleh.2021.06.003
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  Prior work suggests that short sleep and total sleep deprivation are associated with reduced trait Emotional Intelligence (trait EI) but not reduced ability Emotional Intelligence (ability EI). To expand this knowledge base, we investigated the role of habitual sleep quality on trait and ability EI above and beyond the known effects of recent sleep duration..A large sample, comprising 477 healthy adults completed the Pittsburgh Sleep Quality Index (PSQI), Trait Emotional Intelligence Questionnaire (TEIQue; trait EI), and Mayer-Salovey-Caruso Emotional Intelligence Scale (MSCEIT; ability EI)..Bivariate correlation and multiple linear regression showed that recent sleep duration and PSQI sleep quality each independently predicted higher trait EI scores, including Emotionality, Self-Control, Sociability, and Well-being, but were unrelated to ability EI scores..In this large community sample, recent sleep duration and habitual sleep quality both independently associated with self-perceived dispositional aspects of EI (ie, trait EI). In contrast, recent sleep duration and PSQI score were unrelated to more crystalized aspects of EI performance, which encompass the general fund of emotional information and the ability to understand and reason about emotional concepts (ie, ability EI). In sum, self-reported longer sleep duration and better sleep quality were associated with subjective perceptions of better emotional functioning, but was unrelated to performance-based metrics of emotional reasoning.
• Ghani, S. B., Kapoor, A., Tubbs, A. S., Wills, C. C., Karp, J. F., Perlis, M. L., Killgore, W. D., Fernandez, F. X., & Grandner, M. A. (2022). Associations between Insomnia Symptoms and Anxiety Symptoms in Adults in a Community Sample of Southeastern Pennsylvania, USA. Diseases (Basel, Switzerland), 10(4).
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  Although insomnia is reliably associated with anxiety symptoms, aspects of insomnia may differentially relate to one anxiety symptom versus another. Therefore, treatment for insomnia comorbidity with anxiety might be individually tailored to optimize treatment response. Working from this hypothesis, we analyzed data from a survey of 1007 community-dwelling adults. Insomnia was measured using the Insomnia Severity Index (ISI), categorizing items as nighttime disturbances, daytime dysfunction, or self-perceived dissatisfaction. Anxiety symptoms were measured with the Generalized Anxiety Disorder 7-item questionnaire (GAD-7). Linear and binomial logistic regression were used and adjusted for covariates. Post hoc forward stepwise analyses determined which components of the insomnia contributed to individual anxiety symptoms. Significant associations between nighttime disturbance (β = 0.88 [0.44, 1.3]), daytime dysfunction (β = 1.30 [0.81, 1.80]), dissatisfaction (β = 1.20 [0.60, 1.7]) and total GAD-7 score were maintained after adjusting for covariates. Nighttime disturbance was associated with excess worrying, restlessness, irritability, and fear of catastrophe. Daytime dysfunction was associated with all symptoms except for fear of catastrophe, and self-perceived dissatisfaction was associated with all symptoms except irritability. Stepwise analyses revealed that daytime dysfunction and dissatisfaction were most consistently related to anxiety symptoms.Greater attention should be paid to daytime dysfunction in patients with insomnia and anxiety, as improving daytime functioning may improve anxiety.
• Grandner, M. A., Valencia, D. Y., Seixas, A. A., Oliviér, K., Gallagher, R. A., Killgore, W. D., Hale, L., Branas, C., & Alfonso-Miller, P. (2022). Development and Initial Validation of the Assessment of Sleep Environment (ASE): Describing and Quantifying the Impact of Subjective Environmental Factors on Sleep. International journal of environmental research and public health, 19(20).
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  The purpose of this study was to develop and test the reliability and validity of a 13-item self-report Assessment of Sleep Environment (ASE). This study investigates the relationship between subjective experiences of environmental factors (light, temperature, safety, noise, comfort, humidity, and smell) and sleep-related parameters (insomnia symptoms, sleep quality, daytime sleepiness, and control over sleep). The ASE was developed using an iterative process, including literature searches for item generation, qualitative feedback, and pilot testing. It was psychometrically assessed using data from the Sleep and Healthy Activity Diet Environment and Socialization (SHADES) study (N = 1007 individuals ages 22-60). Reliability was determined with an internal consistency and factor analysis. Validity was evaluated by comparing ASE to questionnaires of insomnia severity, sleep quality, daytime sleepiness, sleep control, perceived stress, and neighborhood disorder. The ASE demonstrated high internal consistency and likely reflects a single factor. ASE score was associated with insomnia symptoms (B = 0.09, < 0.0001), sleep quality (B = 0.07, < 0.0001), and sleep control (B = -0.01, < 0.0001), but not daytime sleepiness. The ASE was also associated with perceived stress (B = 0.20, < 0.0001) and neighborhood disorder (B = -0.01, < 0.0001). Among sleep environment factors, only smell was not associated with sleep quality; warmth and safety were negatively associated with sleepiness; and of the sleep environment factors, only light/dark, noise/quiet, and temperature (warm/cool) were not associated with insomnia symptoms. The ASE is a reliable and valid measure of sleep environment. Physical environment (light, temperature, safety, noise, comfort, humidity, and smell) was associated with insomnia symptoms and sleep quality but not sleepiness.
• Hanuka, S., Olson, E. A., Admon, R., Webb, C. A., Killgore, W. D., Rauch, S. L., Rosso, I. M., & Pizzagalli, D. A. (2022). Reduced anhedonia following internet-based cognitive-behavioral therapy for depression is mediated by enhanced reward circuit activation. Psychological medicine, 1-10.
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  Major depressive disorder (MDD) is a highly prevalent psychiatric condition, yet many patients do not receive adequate treatment. Novel and highly scalable interventions such as internet-based cognitive-behavioral-therapy (iCBT) may help to address this treatment gap. Anhedonia, a hallmark symptom of MDD that refers to diminished interest and ability to experience pleasure, has been associated with reduced reactivity in a neural reward circuit that includes medial prefrontal and striatal brain regions. Whether iCBT can reduce anhedonia severity in MDD patients, and whether these therapeutic effects are accompanied by enhanced reward circuit reactivity has yet to be examined.
• Kennedy, K. E., Bastien, C. H., Ruby, P. M., Killgore, W. D., Wills, C. C., & Grandner, M. A. (2022). Nightmare content during the COVID-19 pandemic: Influence of COVID-related stress and sleep disruption in the United States. Journal of sleep research, 31(1), e13439.
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  Nightmares are often associated with psychiatric disorders and acute stress. This study explores how the COVID-19 pandemic may have influenced the content of nightmares. A sample of N = 419 US adults completed online surveys about sleep and COVID-19 experiences. Participants were asked about the degree to which they agreed with statements linking greater general stress, worse overall sleep and more middle-of-the-night insomnia with the COVID-19 pandemic. They were also asked if, during the pandemic, they experienced nightmares related to various themes. Logistic regression analyses examined each nightmare content as outcome and increased stress, worse sleep and more middle-of-the-night insomnia as predictors, adjusted for age, sex and race/ethnicity. Those who reported greater general COVID-related stress were more likely to have nightmares about confinement, failure, helplessness, anxiety, war, separation, totalitarianism, sickness, death, COVID and an apocalypse. Those who reported worsened sleep were more likely to have nightmares about confinement, oppression, failure, helplessness, disaster, anxiety, evil forces, war, domestic abuse, separation, totalitarianism, sickness, death, COVID and an apocalypse. Those who reported worsened middle-of-the-night insomnia were more likely to have nightmares about confinement, oppression, failure, helplessness, disaster, anxiety, war, domestic abuse, separation, totalitarianism, sickness, death, COVID and an apocalypse. These results suggest that increased pandemic-related stress may induce negatively-toned dreams of specific themes. Future investigation might determine whether (and when) this symptom indicates an emotion regulation mechanism at play, or the failure of such a mechanism.
• Kennedy, K. E., Onyeonwu, C., Nowakowski, S., Hale, L., Branas, C. C., Killgore, W. D., Wills, C. C., & Grandner, M. A. (2022). Menstrual regularity and bleeding is associated with sleep duration, sleep quality and fatigue in a community sample. Journal of sleep research, 31(1), e13434.
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  Female menstrual health and its relationship with sleep is an understudied subject. The aim of this investigation was to determine the association between the two in a community sample. Data were obtained from n = 579 menstruating females who participated in the Sleep and Health Activity, Diet, Environment, and Socialization (SHADES) study, a community-based sample of adults aged 22-60 years. Participants were asked, "How regular is your period?", with response choices of "very regular", "mostly regular", "fairly regular" and "not regular". They were also asked, "How much bleeding do you usually experience during your period?" Response choices were: "very heavy", "heavy", "medium", "light" or "very light". These were evaluated as ordinal outcomes. Sleep-related predictors included sleep duration (in hr; ≤ 6 [short], 7-9 [normal] and ≥ 9 [long]), Insomnia Severity Index score, Pittsburgh Sleep Quality Index score, Epworth Sleepiness Scale score and Fatigue Severity Scale score. Covariates included age, education, income, race/ethnicity and body mass index. Short sleep duration was associated with heavier bleeding (odds ratio = 1.46, p = 0.026) and greater cycle irregularity (odds ratio = 1.44, p = 0.031) as compared with normal sleep. Higher Pittsburgh Sleep Quality Index score was associated with greater cycle irregularity (odds ratio = 1.05, p = 0.022). Higher Fatigue Severity Scale score was associated with heavier bleeding (odds ratio = 1.02, p = 0.003) and greater cycle irregularity (odds ratio = 1.02, p = 0.008). Long sleep, Insomnia Severity Index and Epworth Sleepiness Scale were not associated with either outcome. These results demonstrate an association between short sleep duration, poor sleep quality, fatigue, stress and depression with heavier bleeding and menstrual cycle irregularity, highlighting the need for further studies to improve treatment options.
• Killgore, W. D., Alkozei, A., Vanuk, J. R., Reign, D., Grandner, M. A., & Dailey, N. S. (2022). Blue light exposure increases functional connectivity between dorsolateral prefrontal cortex and multiple cortical regions. Neuroreport, 33(5), 236-241.
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  Blue light is a powerful environmental stimulus that can produce significant phase shifts in the circadian rhythm of melatonin and sleep propensity as well as acute effects on alertness of neurobehavioral performance. Here, we undertook an expansion and reanalysis of our previously published findings to examine the effect of acute blue light exposure on the strength of resting-state functional connectivity (rsFC) between a previously identified region of the left dorsolateral prefrontal cortex (DLPFC) and 106 cortical and subcortical regions.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Vanuk, J. R., & Dailey, N. S. (2022). Morning drinking during COVID-19 lockdowns. Psychiatry research, 307, 114320.
• Killgore, W. D., Grandner, M. A., Tubbs, A. S., Fernandez, F. X., Doty, T. J., Capaldi Ii, V. F., & Dailey, N. S. (2022). Sleep loss suicidal ideation: the role of trait extraversion. Frontiers in behavioral neuroscience, 16, 886836.
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  It is known that sleep disturbance is associated with increased suicidal thinking. Moreover, completed suicides, when adjusted for the proportion of the populace that is awake at a given time, are more probable during the late night/early morning hours. Despite these concerns, no studies have examined the role of trait-like individual differences in vulnerability to suicidal ideation during sleep deprivation or insomnia. In two separate studies, we examined whether the trait of extraversion is predictive of changes in suicidal thinking following two nights of sleep deprivation and among individuals meeting the criteria for insomnia. Study 1: Twenty-five healthy military personnel (20 males), ages 20-35 completed the NEO-PI-R Extraversion scale and the Suicidal Ideation (SUI) scale of the Personality Assessment Inventory (PAI). Participants completed 77 h of continuous sleep deprivation. After 56 h of sleep deprivation, participants completed the SUI scale a second time. We predicted a change in SUI scores from baseline extraversion. Study 2: 2,061 adults aged 18-79 (900 males) were divided into two groups based on the clinical threshold (≥ 10) on the Insomnia Severity Index (ISI) and completed measures of extraversion and depression, including the suicide item of the Patient Health Questionnaire-9 (PHQ9). Study 1: After controlling for the caffeine group and changes in PAI Depression, Extraversion scores were used to predict changes in SUI scores using stepwise multiple linear regression. Higher Extraversion was significantly associated with increased non-clinical suicidal ideation following sleep loss, β = 0.463, partial = 0.512, = 0.013. Study 2: After controlling for depression, the effect of insomnia on suicidal ideation was moderated by trait extraversion ( < 0.0001). Overall, the presence or absence of insomnia had little effect on individuals low in trait extraversion (i.e., introverts), but insomnia was associated with significantly higher suicidal ideation among high trait extraverted individuals. Higher trait extraversion was associated with increased vulnerability to suicidal ideation between rested baseline and total sleep deprivation and was associated with greater suicidal ideation among those meeting criteria for clinically severe insomnia. These findings point to a potential trait-like vulnerability factor that may further our understanding of sleep disruption in the phenomenology of suicide.
• Killgore, W. D., Vanuk, J. R., & Dailey, N. S. (2022). Treatment with morning blue light increases left amygdala volume and sleep duration among individuals with posttraumatic stress disorder. Frontiers in behavioral neuroscience, 16, 910239.
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  Posttraumatic stress disorder (PTSD) is associated with numerous cognitive, affective, and psychophysiological outcomes, including problems with sleep and circadian rhythms. We tested the effectiveness of a daily morning blue-light exposure treatment (BLT) versus a matched amber light treatment (ALT) to regulate sleep in individuals diagnosed with PTSD. Moreover, PTSD is also associated with reliable findings on structural neuroimaging scans, including reduced amygdala volumes and other differences in cortical gray matter volume (GMV) that may be indicative of underlying neurobehavioral dysfunctions. We examined the effect of BLT versus ALT on GMV and its association with sleep outcomes.
• Killgore, W., Clark, S., Albertella, L., Kirkham, R., Adler, A., Crampton, J., Drummond, S., Fogarty, G., Gross, J., Zaichkowsky, L., Andersen, J., Bartone, P. (., Boga, D., Bond, J., Brunyé, T., Campbell, M., Ciobanu, L., CRANE, M., Dietrich, A., , Doty, T., et al. (2022). Building a Transdisciplinary Expert Consensus on the Cognitive Drivers of Performance Under Pressure: An International Multi-panel Delphi Study. Frontiers in Psychology. doi:10.3389/fpsyg.2022.1017675
• Killgore, W., Tubbs, A., Grandner, M. A., Ghani, S., Jean-Louis, G., & Fernandez, F. (2022). Abstract MP55: Declining Annual Trends In Us Daily Sleep Duration Are Greater Among Racial/ethnic Minorities: Implications For Cardiometabolic Disease Disparities. Circulation, 145(Suppl_1). doi:10.1161/circ.145.suppl_1.mp55
• Raikes, A. C., Hernandez, G. D., Mullins, V. A., Wang, Y., Lopez, C., Killgore, W. D., Chilton, F. H., & Brinton, R. D. (2022). Effects of docosahexaenoic acid and eicosapentaoic acid supplementation on white matter integrity after repetitive sub-concussive head impacts during American football: Exploratory neuroimaging findings from a pilot RCT. Frontiers in neurology, 13, 891531.
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  Repetitive sub-concussive head impacts (RSHIs) are common in American football and result in changes to the microstructural integrity of white matter. Both docosahexaenoic acid (DHA) and eicosapentaoic acid (EPA) supplementation exerted neuroprotective effects against RSHIs in animal models and in a prior study in football players supplemented with DHA alone.
• Smith, R., Persich, M., Lane, R. D., & Killgore, W. D. (2022). Higher emotional awareness is associated with greater domain-general reflective tendencies. Scientific reports, 12(1), 3123.
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  The tendency to reflect on the emotions of self and others is a key aspect of emotional awareness (EA)-a trait widely recognized as relevant to mental health. However, the degree to which EA draws on general reflective cognition vs. specialized socio-emotional mechanisms remains unclear. Based on a synthesis of work in neuroscience and psychology, we recently proposed that EA is best understood as a learned application of domain-general cognitive processes to socio-emotional information. In this paper, we report a study in which we tested this hypothesis in 448 (125 male) individuals who completed measures of EA and both general reflective cognition and socio-emotional performance. As predicted, we observed a significant relationship between EA measures and both general reflectiveness and socio-emotional measures, with the strongest contribution from measures of the general tendency to engage in effortful, reflective cognition. This is consistent with the hypothesis that EA corresponds to the application of general reflective cognitive processes to socio-emotional signals.
• Tubbs, A. S., Killgore, W. D., Karp, J. F., Fernandez, F. X., & Grandner, M. A. (2022). Insomnia and the Interpersonal Theory of suicide among civilians, service members, and veterans. Journal of psychiatric research, 155, 534-541.
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  Insomnia is associated with suicide risk in civilian and military populations. Thwarted belongingness is proposed as a mediator of this relationship under the Interpersonal Theory of Suicide (IPTS). The present study explored how insomnia relates to suicidal ideation in conjunction with thwarted belongingness among civilians, Service members, and Veterans.
• Vanuk, J. R., Pace-Schott, E. F., Bullock, A., Esbit, S., Dailey, N. S., & Killgore, W. D. (2022). Morning blue light treatment improves sleep complaints, symptom severity, and retention of fear extinction memory in post-traumatic stress disorder. Frontiers in behavioral neuroscience, 16, 886816.
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  Disrupted sleep is a major feature in numerous clinical disorders and is related to decrements in affective memory processing. The prevalence of sleep disruption in post-traumatic stress disorder (PTSD) is suggested to be a key feature that exacerbates the impaired ability to recall extinction memories during experimental fear conditioning. We hypothesized that an intervention employing blue-wavelength light therapy (BLT) to regulate sleep and stabilize circadian rhythms in patients with PTSD (i.e., via regulated morning exposure) would be associated with PTSD symptom improvement, decreased sleep-related complaints, as well as improved consolidation and retention of extinction memories relative to a fear conditioning/extinction paradigm. Eighty-two individuals with PTSD underwent a well-validated fear conditioning/extinction protocol with subsequent assignment to receive morning BLUE (BLT) or placebo AMBER (ALT) light therapy daily for 30-min over 6-weeks. Participants returned after the intervention for post-treatment extinction recall, comprised of exposure to the previously conditioned stimuli, with the difference in skin conductance response between the "extinguished" and the "never-extinguished" stimuli at follow-up. Participants also viewed previously conditioned stimuli in a novel context during a functional magnetic resonance imaging (fMRI) scan. BLUE light therapy was associated with improvements relative to correlated decreases between PTSD symptoms and sleep-related complaints. Participants receiving BLT also sustained retention of the extinction memory, while those in the placebo amber light treatment group showed impairment, characterized by the restoration of the extinguished fear response after 6-weeks. Participants in the ALT also demonstrated greater reactivity in the left insula when viewing the previously extinguished fear-conditioned stimuli in a novel context. Daily BLUE-wavelength morning light exposure was associated with greater retention of extinction learning in patients with PTSD when compared to ALT, as supported by both autonomic and neurobiological reactivity. We speculate that improved sleep facilitated by a stabilized circadian rhythm, after fear-learning, led to greater consolidation of the fear extinction memory, decreased PTSD symptom presentation, and associated decreases in sleep-related complaints. Prominent exposure treatments for PTSD incorporate principles of fear extinction, and our findings suggest that blue light treatment may facilitate treatment gains by promoting the consolidation of extinction memories via improved sleep.
• Vanuk, J. R., Reign, D., Killgore, W. D., Grandner, M. A., Dailey, N. S., & Alkozei, A. (2022). Blue light exposure increases functional connectivity between dorsolateral prefrontal cortex and multiple cortical regions.. Neuroreport, 33(5), 236-241. doi:10.1097/wnr.0000000000001774
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  Blue light is a powerful environmental stimulus that can produce significant phase shifts in the circadian rhythm of melatonin and sleep propensity as well as acute effects on alertness of neurobehavioral performance. Here, we undertook an expansion and reanalysis of our previously published findings to examine the effect of acute blue light exposure on the strength of resting-state functional connectivity (rsFC) between a previously identified region of the left dorsolateral prefrontal cortex (DLPFC) and 106 cortical and subcortical regions..Twenty-nine healthy adults (16 men and 13 women; age 18-32 years) completed a psychomotor vigilance test (PVT) before and after a single 30-min exposure to either blue (λ = 469 nm; n = 17) or amber wavelength (λ = 578 nm; n = 12) light, immediately followed by an rsFC scan..Compared with amber light, blue light exposure produced significantly greater functional connectivity between the left DLPFC seed region and 30 cortical and subcortical regions (P < 0.05; false discovery rate-corrected). Although neurobehavioral performance did not differ between light conditions, only those exposed to blue light showed a significant association between rsFC and sustained PVT performance. Better sustained PVT performance was associated with greater connectivity between the left DLPFC and regions associated with visuospatial awareness/motion detection (right temporal-occipital middle temporal gyrus) and memory (left hippocampus), as well as reduced connectivity in a circuit associated with cognitive rumination and distraction (left parahippocampal gyrus)..Findings suggest that blue-wavelength light may facilitate acute alertness and improved cognitive performance through enhanced rsFC between the left DLPFC and cortical regions associated with visuospatial awareness.
• Alkozei, A., Dailey, N. S., Bajaj, S., Vanuk, J. R., Raikes, A. C., & Killgore, W. D. (2021). Exposure to Blue Wavelength Light Is Associated With Increases in Bidirectional Amygdala-DLPFC Connectivity at Rest. Frontiers in neurology, 12, 625443.
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  Blue wavelength light has been used successfully as a treatment method for certain mood disorders, but, the underlying mechanisms behind the mood enhancing effects of light remain poorly understood. We investigated the effects of a single dose of 30 min of blue wavelength light ( = 17) vs. amber wavelength light ( = 12) exposure in a sample of healthy adults on subsequent resting-state functional and directed connectivity, and associations with changes in state affect. Individuals who received blue vs. amber wavelength light showed greater positive connectivity between the right amygdala and a region within the left dorsolateral prefrontal cortex (DLPFC). In addition, using granger causality, the findings showed that individuals who received blue wavelength light displayed greater bidirectional information flow between these two regions relative to amber light. Furthermore, the strength of amygdala-DLPFC functional connectivity was associated with greater decreases in negative mood for the blue, but not the amber light condition. Blue light exposure may positively influence mood by modulating greater information flow between the amygdala and the DLPFC, which may result in greater engagement of cognitive control strategies that are needed to perceive and regulate arousal and mood.
• Bajaj, S., & Killgore, W. D. (2021). Association between emotional intelligence and effective brain connectome: A large-scale spectral DCM study. NeuroImage, 229, 117750.
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  Emotional Intelligence (EI) is a well-documented aspect of social and interpersonal functioning, but the underlying neural mechanisms for this capacity remain poorly understood. Here we used advanced brain connectivity techniques to explore the associations between EI and effective connectivity (EC) within four functional brain networks.
• Bajaj, S., Raikes, A. C., Razi, A., Miller, M. A., & Killgore, W. D. (2021). Blue-Light Therapy Strengthens Resting-State Effective Connectivity within Default-Mode Network after Mild TBI. Journal of central nervous system disease, 13, 11795735211015076.
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  Emerging evidence suggests that post concussive symptoms, including mood changes, may be improved through morning blue-wavelength light therapy (BLT). However, the neurobiological mechanisms underlying these effects remain unknown. We hypothesize that BLT may influence the effective brain connectivity (EC) patterns within the default-mode network (DMN), particularly involving the medial prefrontal cortex (MPFC), which may contribute to improvements in mood.
• Charest, J., Bastien, C. H., Ellis, J. G., Killgore, W. D., & Grandner, M. A. (2021). The Impact of Perceived Sleep, Mood and Alcohol Use on Verbal, Physical and Sexual Assault Experiences among Student Athletes and Student Non-Athletes. International journal of environmental research and public health, 18(6).
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  Previous research has shown that student athletes are more likely to be involved in a physical altercation or be a victim of verbal, physical and/or sexual abuse than student non-athletes, which can have long-lasting negative effects on mood, behavior and quality of life. In addition, among college students, sleep difficulties are ubiquitous and may deteriorate the unique life experience that university represents. The influences of poor sleep quality, mood and alcohol consumption related to these events are examined here between student athletes and student non-athletes. A series of hierarchical logistic regressions explored the relationship between verbal, physical and sexual assault risk factors. Results suggest that poor sleep, alcohol consumption and mood are all associated with exposure to a physical altercation or episode of abuse, irrespective of athlete status. Results also show that variables targeting self-reported difficulty sleeping and experiences of verbal, physical and sexual assault were positively associated. However, given the cross-sectional nature of the study, it is impossible to establish the direction of these relationships.
• Ghani, S. B., Taneja, K., Wills, C. C., Tubbs, A. S., Delgadillo, M. E., Valencia, D., Halane, M., Killgore, W. D., & Grandner, M. A. (2021). Culturally-consistent diet among individuals of Mexican descent at the US-Mexico border is associated with sleep duration and snoring. BMC nutrition, 7(1), 53.
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  Existing studies show that consuming food consistent with one's culture reduces cardiometabolic risk. However, few studies have assessed whether these dietary choices influence sleep health. Accordingly, this study assessed how Mexican food consumption by individuals of Mexican descent residing at the US-Mexico border, was associated with various measures of sleep, after accounting for acculturation.
• Grandner, M. A., Gehrels, J. A., Alfonso-miller, P., Carrazco, N., Branas, C. C., Hale, L., Gallagher, R. A., Killgore, W. D., Patterson, F., Chakravorty, S., Haynes, P. L., Rhee, J. U., & Nunez, A. (2021). Smoke at night and sleep worse? The associations between cigarette smoking with insomnia severity and sleep duration.. Sleep health, 7(2), 177-182. doi:10.1016/j.sleh.2020.10.006
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  Insomnia is a clinically verified nicotine withdrawal symptom. As nicotine is a stimulant, it is plausible that smoking at night could disturb sleep more than smoking at earlier times of the day, but this remains empirically unclear. This study examined smoking status and its associations with insomnia severity and sleep duration while considering the potential role of smoking time..Data were derived from the Sleep and Healthy Activity Diet Environment and Socialization study, a community-based study of 1007 adults (nnonsmokers = 818; nsmokers = 189) aged 22-60 from the Philadelphia area. Smoking status and time of smoking were self-reported. Insomnia was assessed with the Insomnia Severity Index and categorized as none, mild, and moderate-to-severe. Sleep duration was assessed with one item from the National Health and Nutrition Examination Survey and categorized as very short, short, normal, and long. Ordinal and multinomial logistic regressions were used to determine the association of smoking status including smoking time with insomnia severity and sleep duration controlling for sociodemographic covariates..Compared to nonsmoking, smoking was associated with experiencing increased insomnia (odds ratio = 2.5, 95% confidence interval [CI] 1.9, 3.4, P < .001) as well as very short (relative risk ratio = 1.9, 95% CI 1.1, 3.3) and short (relative risk ratio = 1.5, 95% CI 1.0, 2.3) sleep (vs normal sleep duration). Night-time smoking was significantly associated with greater insomnia and shorter sleep duration..Findings provide evidence that smoking is associated with increased insomnia severity and shorter sleep duration, particularly nightly smoking. Sleep health should be considered in smoking cessation efforts.
• Grandner, M. A., Hall, C., Jaszewski, A., Alfonso-Miller, P., Gehrels, J. A., Killgore, W. D., & , A. A. (2021). Mental Health in Student Athletes: Associations With Sleep Duration, Sleep Quality, Insomnia, Fatigue, and Sleep Apnea Symptoms. Athletic training & sports health care, 13(4), e159-e167.
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  To quantify the relationship between sleep difficulties and poor mental health among student athletes using validated measures.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., & Dailey, N. S. (2021). Mental Health During the First Weeks of the COVID-19 Pandemic in the United States. Frontiers in psychiatry, 12, 561898.
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  By March 2020, the World Health Organization declared the COVID-19 crisis as a worldwide pandemic and many local governments instituted stay-at-home orders and closed non-essential businesses. Within the United States, tens of millions of workers lost their jobs and financial security during the first few weeks of the national response, in an attempt to slow the global pandemic. Because of the enormity of the pandemic and its potential impact on mental health, the objective of the present study was to document the prevalence of mental health problems and their association with pandemic-related job loss during the third week of the nationwide shutdown. Mental health was assessed via online questionnaires among a representative sample of 1,013 U.S. adults on April 9-10, 2020. Rates of clinically significant mental health outcomes were compared between participants who lost their job as a result of COVID-19 restrictions (17.4%) vs. those who did not (82.6%). Bivariate multiple logistic regression identified factors that were predictive of, and protective against, mental health problems. The prevalence of clinically significant symptoms was significantly higher than prior population estimates, ranging from 27 to 32% for depression, 30 to 46% for anxiety disorders, 15 to 18% for acute/post-traumatic stress, 25% for insomnia, and 18% for suicidal ideation. Prevalence estimates were 1.5-1.7 times higher for those who reported job loss due to COVID-19 restrictions than those who did not. Mental health problems were predicted by worry over financial instability, insomnia, social isolation, and alcohol consumption, while getting outside more often, perceived social support, and older age were protective against these problems. During the first 3 weeks of lockdowns/stay-at-home restrictions, mental health problems, including depression, anxiety, insomnia, and acute stress reactions were notably elevated relative to prior population estimates. Job loss related to the nationwide shutdown was particularly associated with poorer mental health. These findings provide a baseline of mental health functioning during the first weeks of the national emergency and lockdown orders in response to COVID-19.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., & Dailey, N. S. (2021). The COVID-19 Vaccine Is Here-Now Who Is Willing to Get It?. Vaccines, 9(4).
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  The U.S. vaccine campaign against COVID-19 began in December 2020, but many individuals seem reluctant to get vaccinated. During the first week of the vaccination campaign, we collected data from 1017 individuals with an online survey to identify factors that were associated with willingness to get the vaccine once it is available. Most participants (55.3%) were willing to get the vaccine, although 46.2% also expressed some fear of the vaccine. Political ideology was by far the most consistent predictor of both willingness to be vaccinated and fear of the vaccine, followed by participant sex, education level, income, and race/ethnicity. Our findings suggest that, for the vaccine campaign to be broadly supported and successful, it will be important for frontline healthcare workers to discuss the role of inoculation for COVID-19 in a manner consistent with each individual patient's political and sociological worldview.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Anlap, I., & Dailey, N. S. (2021). Increasing aggression during the COVID-19 lockdowns. Journal of affective disorders reports, 5, 100163.
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  To combat the spread of COVID-19, many communities implemented restrictions on personal movement, often referred to as "lockdowns." We hypothesized that continued lockdowns might be associated with increased feelings of aggression.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Lucas, D. A., & Dailey, N. S. (2021). Alcohol dependence during COVID-19 lockdowns. Psychiatry research, 296, 113676.
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  To determine whether the past half-year of COVID-19-related lockdowns, stay-at-home orders, and social isolation were associated with changes in high-risk alcohol use, a total of 5,931 individuals completed the Alcohol Use Disorders Identification Test (AUDIT) at one of six time points from April through September 2020. Over the 6-month period, hazardous alcohol use and likely dependence increased month-by-month for those under lockdowns compared to those not under restrictions. This increase in harmful alcohol use and related behaviors is likely to have prolonged adverse psychosocial, interpersonal, occupational, and health impacts as the world attempts to recover from the pandemic crisis.
• Killgore, W. D., Vanuk, J. R., Persich, M. R., Cloonan, S. A., Grandner, M. A., & Dailey, N. S. (2021). Sleep quality and duration are associated with greater trait emotional intelligence. Sleep health.
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  Prior work suggests that short sleep and total sleep deprivation are associated with reduced trait Emotional Intelligence (trait EI) but not reduced ability Emotional Intelligence (ability EI). To expand this knowledge base, we investigated the role of habitual sleep quality on trait and ability EI above and beyond the known effects of recent sleep duration.
• Krupp, K., Madhivanan, P., Killgore, W. D., Ruiz, J. M., Carvajal, S., Coull, B. M., & Grandner, M. A. (2021). Neurological Manifestations in COVID-19: An Unrecognized Crisis in Our Elderly?. Advances in geriatric medicine and research, 3(3).
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  As of December 2020, there were more than 900,000 COVID-19 hospitalizations in the US with about 414,000 among individuals aged 65 years and older. Recent evidence suggests a growing number of older patients continue to suffer serious neurological comorbidities including polyneuropathy, cerebrovascular disease, central nervous system infection, cognitive deficits, and fatigue following discharge. Studies suggest that complaints manifest late in disease and persist beyond resolution of acute COVID-19 symptoms. Recent research reports that neurocognitive symptoms are correlated with severe disease, older age, male gender, and comorbidities including hypertension, renal failure, and neoplastic disease. The underlying causes are unclear, but current hypotheses include hypoxic-ischemic brain injury, immunopathological mechanisms, and neurotropism of SARS-CoV-2 infection. There is a pressing need for more research into the underlying mechanisms of post-COVID-19 neurological sequela, particularly in the elderly, a population already burdened with neurocognitive disorders.
• Persich, M. R., Smith, R., Cloonan, S. A., Woods-Lubbert, R., Strong, M., & Killgore, W. D. (2021). Emotional intelligence training as a protective factor for mental health during the COVID-19 pandemic. Depression and anxiety, 38(10), 1018-1025.
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  The COVID-19 pandemic has presented a major challenge to mental health and emotional wellbeing. The present study examined whether training in emotional intelligence (EI) skills, provided before the pandemic, would serve as a protective factor for sustaining mental health during the COVID-19 crisis.
• Raikes, A. C., Dailey, N. S., Forbeck, B., Alkozei, A., & Killgore, W. D. (2021). Daily Morning Blue Light Therapy for Post-mTBI Sleep Disruption: Effects on Brain Structure and Function. Frontiers in neurology, 12, 625431.
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  Mild traumatic brain injuries (mTBIs) are associated with novel or worsened sleep disruption. Several studies indicate that daily morning blue light therapy (BLT) is effective for reducing post-mTBI daytime sleepiness and fatigue. Studies demonstrating changes in brain structure and function following BLT are limited. The present study's purpose is to identify the effect of daily morning BLT on brain structure and functional connectivity and the association between these changes and self-reported change in post-mTBI daytime sleepiness. A total of 62 individuals recovering from a mTBI were recruited from two US cities to participate in a double-blind placebo-controlled trial. Eligible individuals were randomly assigned to undergo 6 weeks of 30 min daily morning blue or placebo amber light therapy (ALT). Prior to and following treatment all individuals completed a comprehensive battery that included the Epworth Sleepiness Scale as a measure of self-reported daytime sleepiness. All individuals underwent a multimodal neuroimaging battery that included anatomical and resting-state functional magnetic resonance imaging. Atlas-based regional change in gray matter volume (GMV) and region-to-region functional connectivity from baseline to post-treatment were the primary endpoints for this study. After adjusting for pre-treatment GMV, individuals receiving BLT had greater GMV than those receiving amber light in 15 regions of interest, including the right thalamus and bilateral prefrontal and orbitofrontal cortices. Improved daytime sleepiness was associated with greater GMV in 74 ROIs, covering many of the same general regions. Likewise, BLT was associated with increased functional connectivity between the thalamus and both prefrontal and orbitofrontal cortices. Improved daytime sleepiness was associated with increased functional connectivity between attention and cognitive control networks as well as decreased connectivity between visual, motor, and attention networks (all FDR corrected < 0.05). Following daily morning BLT, moderate to large increases in both gray matter volume and functional connectivity were observed in areas and networks previously associated with both sleep regulation and daytime cognitive function, alertness, and attention. Additionally, these findings were associated with improvements in self-reported daytime sleepiness. Further work is needed to identify the personal characteristics that may selectively identify individuals recovering from a mTBI for whom BLT may be optimally beneficial.
• Raikes, A. C., Dailey, N. S., Shane, B. R., Forbeck, B., Alkozei, A., & Killgore, W. D. (2020). Daily Morning Blue Light Therapy Improves Daytime Sleepiness, Sleep Quality, and Quality of Life Following a Mild Traumatic Brain Injury. The Journal of head trauma rehabilitation, 35(5), E405-E421.
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  Identify the treatment effects of 6 weeks of daily 30-minute sessions of morning blue light therapy compared with placebo amber light therapy in the treatment of sleep disruption following mild traumatic brain injury.
• Smith, R., Taylor, S., Wilson, R. C., Chuning, A. E., Persich, M. R., Wang, S., & Killgore, W. D. (2021). Lower Levels of Directed Exploration and Reflective Thinking Are Associated With Greater Anxiety and Depression. Frontiers in psychiatry, 12, 782136.
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  Anxiety and depression are often associated with strong beliefs that entering specific situations will lead to aversive outcomes - even when these situations are objectively safe and avoiding them reduces well-being. A possible mechanism underlying this maladaptive avoidance behavior is a failure to reflect on: (1) appropriate levels of uncertainty about the situation, and (2) how this uncertainty could be reduced by seeking further information (i.e., exploration). To test this hypothesis, we asked a community sample of 416 individuals to complete measures of reflective cognition, exploration, and symptoms of anxiety and depression. Consistent with our hypotheses, we found significant associations between each of these measures in expected directions (i.e., positive relationships between reflective cognition and strategic information-seeking behavior or "directed exploration", and negative relationships between these measures and anxiety/depression symptoms). Further analyses suggested that the relationship between directed exploration and depression/anxiety was due in part to an ambiguity aversion promoting exploration in conditions where information-seeking was not beneficial (as opposed to only being due to under-exploration when more information would aid future choices). In contrast, reflectiveness was associated with greater exploration in appropriate settings and separately accounted for differences in reaction times, decision noise, and choice accuracy in expected directions. These results shed light on the mechanisms underlying information-seeking behavior and how they may contribute to symptoms of emotional disorders. They also highlight the potential clinical relevance of individual differences in reflectiveness and exploration and should motivate future research on their possible contributions to vulnerability and/or maintenance of affective disorders.
• Wills, C., Ghani, S., Tubbs, A., Fernandez, F. X., Athey, A., Turner, R., Robbins, R., Patterson, F., Warlick, C., Alfonso-Miller, P., Killgore, W. D., & Grandner, M. A. (2021). Chronotype and social support among student athletes: impact on depressive symptoms. Chronobiology international, 38(9), 1319-1329.
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  Previous studies have shown individuals with evening chronotype to have a greater likelihood for depression (self-reported and clinical ratings), especially in young adults. However, the mechanisms for this relationship remain unknown. Low levels of social support may be a plausible mechanism: young adults with evening chronotypes are awake when others are sleeping, which may lead to feelings of isolation or low support. This study examined links between chronotype, depression, and social support in relationship subtypes within a group of university student athletes. Data were obtained from 189 NCAA Division-I student athletes across all sports. Chronotype was assessed with the Circadian Energy Scale and ranged from -2 (definitely morning type) to +2 (definitely evening type). Depressive symptoms were assessed with Center for Epidemiological Studies Depression scale. Social support was assessed with the Multidimensional Scale of Perceived Social Support, which included subscales for Family, Friends, and Significant Other. A subscale for Team was created using the items from the Friends subscale (changing the word "friends" to "teammates"). Regression analyses adjusted for age, sex, and minority status. More evening chronotype was associated with higher reported depressive symptoms ( = .018), lower overall perceived social support ( = .001), and lower perceived social support specifically provided by family (
• Bajaj, S., & Killgore, W. D. (2020). Sex differences in limbic network and risk-taking propensity in healthy individuals. Journal of neuroscience research, 98(2), 371-383.
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  Little is known about the structural neural substrates that may contribute to sex differences in risk-taking propensity (RTP). A close association between risk-seeking behavior and the emotional-regulation network led us to hypothesize that the sex differences in RTP would be associated with sex differences in brain morphometry of the limbic network (LN). We collected RTP scores using the bubble sheet version of the evaluation of risk (EVAR) scale and neuroanatomical data from 57 healthy individuals (29 males). The EVAR scale included sub-scales measuring recklessness/impulsivity, self-confidence, and need for control (NFC). We observed significant sex differences in NFC showing greater desire for control and dominance in males than females (multivariate analysis of covariance, MANCOVAN: p = .01). Morphometry analysis showed that it was only the right LN, which showed significant sex differences in normalized surface area, normalized cortical volume, and adjusted mean curvature index (females > males) at p 
• Grandner, M. A., Olivier, K., Gallagher, R., Hale, L., Barrett, M., Branas, C., Killgore, W. D., Parthasarathy, S., Gehrels, J. A., & Alfonso-Miller, P. (2020). Quantifying impact of real-world barriers to sleep: The Brief Index of Sleep Control (BRISC). Sleep health, 6(5), 587-593.
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  Lack of control over sleep may contribute to population-level sleep disturbances, yet relatively little work has explored the degree to which an individual's sense of control over their sleep may represent an important factor.
• Khader, W. S., Fernandez, F. X., Seixas, A., Knowlden, A., Ellis, J., Williams, N., Hale, L., Branas, C., Perlis, M., Jean-Louis, G., Killgore, W. D., Alfonso-Miller, P., & Grandner, M. A. (2020). What makes people want to make changes to their sleep? Assessment of perceived risks of insufficient sleep as a predictor of intent to improve sleep. Sleep health.
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  The objective of the present study is to identify which underlying beliefs about the impact of sleep on health may motivate change in sleep behavior.
• Khader, W. S., Tubbs, A. S., Haghighi, A., Athey, A. B., Killgore, W. D., Hale, L., Perlis, M. L., Gehrels, J. A., Alfonso-Miller, P., Fernandez, F. X., & Grandner, M. A. (2020). Onset insomnia and insufficient sleep duration are associated with suicide ideation in university students and athletes. Journal of affective disorders, 274, 1161-1164.
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  Previous work has shown that poor sleep is a prospective risk factor for suicide in clinical populations and might contribute to risk in the general population. The present study evaluated whether sleep distress, onset insomnia, and insufficient sleep are associated with suicide ideation in university students and athletes participating in the 2011-2014 National College Health Assessment (NCHA; n = 113,185).
• Killgore, W. D. (2020). Blue Light Therapy Enhances Sleep and Fear Extinction Recall in PTSD. Biological Psychiatry, 87(9), S70-S71. doi:10.1016/j.biopsych.2020.02.1206
• Killgore, W. D. (2020). Lightening the mood: evidence for blue light exposure in the treatment of post-concussion depression. Expert review of neurotherapeutics, 20(11), 1081-1083.
• Killgore, W. D., & Kamimori, G. H. (2020). Multiple caffeine doses maintain vigilance, attention, complex motor sequence expression, and manual dexterity during 77 hours of total sleep deprivation. Neurobiology of sleep and circadian rhythms, 9, 100051.
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  Sleep deprivation (SD) and fatigue have detrimental effects on performance in operational settings. Few studies have investigated the cumulative effects of SD and fatigue on performance under heavy workload demands. Therefore, we investigated the efficacy of multiple repeated doses of caffeine as a countermeasure to SD and fatigue during 77 h total SD (TSD) during the early morning hours. Twenty-three males and females, 18 - 35 years of age, who identified as moderate caffeine consumers completed the Psychomotor Vigilance Task (PVT) 141 times during the experimental test period. Caffeine was administered in a multi-dose paradigm over three nights without sleep. Participants received either caffeine (200 mg) or placebo at the beginning of each 2-h test block from 0100 - 0900 (800 mg total per night). While PVT speed declined for both groups across all 3 nights, the caffeine group consistently out-performed the placebo group. Caffeine maintained attentiveness (1-5 s lapses) on night 1, but this advantage was lost on nights 2 and 3. Caffeine outperformed placebo for responsive lapses (5-9 s lapses) across all three nights, but caffeine performance was still notably worse than at baseline. Prolonged non-responsive lapses (beyond 10 s) were only reduced by caffeine on night 2. Caffeine was more effective than placebo across all nights at sustaining completion speed of a complex motor sequence task and a manual coordination task. Essentially, caffeine is an effective countermeasure for SD, as it mitigates declines in speed and failures to respond, and sustains motor planning and coordination. However, caffeine does not restore normal functioning during SD and cannot be considered as a replacement for sleep.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., & Dailey, N. S. (2020). Loneliness: A signature mental health concern in the era of COVID-19. Psychiatry research, 290, 113117.
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  In response to the COVID-19 pandemic, most communities in the United States imposed stay-at-home orders to mitigate the spread of the novel coronavirus, potentially leading to chronic social isolation. During the third week of shelter-in-place guidelines, 1,013 U.S. adults completed the UCLA Loneliness Scale-3 and Public Health Questionnaire (PHQ-9). Loneliness was elevated, with 43% of respondents scoring above published cutoffs, and was strongly associated with greater depression and suicidal ideation. Loneliness is a critical public health concern that must be considered during the social isolation efforts to combat the pandemic.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Allbright, M. C., & Dailey, N. S. (2020). Trends in suicidal ideation over the first three months of COVID-19 lockdowns. Psychiatry research, 293, 113390.
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  To reduce viral spread during the first months of the COVID-19 pandemic, most communities across the U.S. engaged in some form of stay-at-home restrictions or lockdowns that limited social interaction and movement outside the home. To determine the effect of these restrictions on suicidal ideation, a total of 3,120 individuals completed the Patient Health Questionnaire (PHQ-9) at one of three time points from April through June 2020. The percentage of respondents endorsing suicidal ideation was greater with each passing month for those under lockdown or shelter-in-place restrictions due to the novel coronavirus, but remained relatively stable and unchanged for those who reported no such restrictions. Public health policy and routine clinical care need to address the potential for increased suicidal thinking among those experiencing prolonged restrictions of normal social contact.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Fernandez, F., Grandner, M. A., & Dailey, N. S. (2020). Suicidal ideation during the COVID-19 pandemic: The role of insomnia. Psychiatry research, 290, 113134.
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  There is growing concern over the potential for increased suicide risk in vulnerable populations as the COVID-19 pandemic unfolds. To contextualize this risk during the first weeks of the nationwide lockdown efforts, we had 1,013 U.S. adults complete questionnaires assessing worries over COVID-19, insomnia severity, and suicidal ideation. Anxiety about COVID-19 correlated positively with insomnia severity and suicidal ideation. Analysis revealed that the statistical association between pandemic fears and suicidal thinking was fully accounted for by insomnia severity, suggesting that interventions aimed at improving sleep may be useful in reducing suicide risk during the current pandemic.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Lucas, D. A., & Dailey, N. S. (2020). Loneliness during the first half-year of COVID-19 Lockdowns. Psychiatry research, 294, 113551.
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  During the first 6-months of the COVID-19 pandemic, the primary weapons against the spread of the virus have included local government orders for restriction of movement and broad implementation of face masks and social distancing policies. While some early reports suggested increases in loneliness during the pandemic restrictions, others reported no changes. Here, we provide an update on self-reported loneliness over the first 6-months of community lockdown restrictions from a nationwide sample of 6,186 U.S. adults who completed the UCLA Loneliness Scale-3 and Public Health Questionnaire-9 during the pandemic. Loneliness scores increased significantly from April through September 2020 and were significantly higher for those reporting they were under stay-at-home, shelter-in-place, or lockdown orders compared to those reporting no restrictions. Greater loneliness was positively correlated with depression and suicidal ideation. Loneliness has increased over the first half-year of the pandemic, particularly for those under lockdown restrictions, and remains a significant mental health concern.
• Killgore, W. D., Cloonan, S. A., Taylor, E. C., Miller, M. A., & Dailey, N. S. (2020). Three months of loneliness during the COVID-19 lockdown. Psychiatry research, 293, 113392.
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  The majority of the U.S. population has been under stay-at-home restrictions to reduce the spread of COVID-19 since March 2020. Over the first three months of restrictions, 3,121 U.S. adults completed the UCLA Loneliness Scale-3 and Patient Health Questionnaire-9 (PHQ-9). Despite relaxation of lockdowns and shelter-in-place orders over that time, loneliness scores increased significantly, particularly from April to May 2020, and appear to have plateaued by June. Loneliness was correlated with depression and suicidal ideation at all time points and was most prevalent among individuals who reported that they were still under community restrictions to socially isolate due to the novel coronavirus. Loneliness remains elevated despite the reopening of many communities.
• Killgore, W. D., Dailey, N. S., Raikes, A. C., Vanuk, J. R., Taylor, E., & Alkozei, A. (2020). Blue light exposure enhances neural efficiency of the task positive network during a cognitive interference task. Neuroscience letters, 735, 135242.
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  Exposure to light, particularly blue-wavelength light, has been shown to acutely increase brain activation, alertness, and some elementary aspects of cognitive performance such as working memory and emotional anticipation. Whether blue light exposure can have effects on brain activation and performance during more complex cognitive control tasks up to 30 min after light cessation is unknown. In a sample of 32 healthy adults, we examined the effects of a 30 min exposure to either blue (n = 16) or amber control (n = 16) light on subsequent brain activation and performance during the Multi-Source Interference Task (MSIT) measured a half-hour after light exposure. Performance on the MSIT did not differ between the blue and amber conditions. However, brain activation within the task positive network (TPN) to the interference condition was significantly lower in the blue relative to the amber condition, while no group differences were observed for suppression of the default mode network (DMN). These findings suggest that, compared to control, a single exposure to blue light was associated with enhanced neural efficiency, as demonstrated by reduced TPN activation to achieve the same level of performance. Blue light may be an effective method for optimizing neurocognitive performance under some conditions.
• Killgore, W. D., Taylor, E. C., Cloonan, S. A., & Dailey, N. S. (2020). Psychological resilience during the COVID-19 lockdown. Psychiatry research, 291, 113216.
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  Some individuals are more psychologically resilient to adversity than others, an issue of great importance during the emerging mental health issues associated with the COVID-19 pandemic. To identify factors that may contribute to greater psychological resilience during the first weeks of the nation-wide lockdown efforts, we asked 1,004 U.S. adults to complete assessments of resilience, mental health, and daily behaviors and relationships. Average resilience was lower than published norms, but was greater among those who tended to get outside more often, exercise more, perceive more social support from family, friends, and significant others, sleep better, and pray more often. Psychological resilience in the face of the pandemic is related to modifiable factors.
• Killgore, W. D., Vanuk, J. R., Shane, B. R., Weber, M., & Bajaj, S. (2020). A randomized, double-blind, placebo-controlled trial of blue wavelength light exposure on sleep and recovery of brain structure, function, and cognition following mild traumatic brain injury. Neurobiology of disease, 134, 104679.
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  Sleep and circadian rhythms are among the most powerful but least understood contributors to cognitive performance and brain health. Here we capitalize on the circadian resetting effect of blue-wavelength light to phase shift the sleep patterns of adult patients (aged 18-48 years) recovering from mild traumatic brain injury (mTBI), with the aim of facilitating recovery of brain structure, connectivity, and cognitive performance. During a randomized, double-blind, placebo-controlled trial of 32 adults with a recent mTBI, we compared 6-weeks of daily 30-min pulses of blue light (peak λ = 469 nm) each morning versus amber placebo light (peak λ = 578 nm) on neurocognitive and neuroimaging outcomes, including gray matter volume (GMV), resting-state functional connectivity, directed connectivity using Granger causality, and white matter integrity using diffusion tensor imaging (DTI). Relative to placebo, morning blue light led to phase-advanced sleep timing, reduced daytime sleepiness, and improved executive functioning, and was associated with increased volume of the posterior thalamus (i.e., pulvinar), greater thalamo-cortical functional connectivity, and increased axonal integrity of these pathways. These findings provide insight into the contributions of the circadian and sleep systems in brain repair and lay the groundwork for interventions targeting the retinohypothalamic system to facilitate injury recovery.
• Martin, L. F., Patwardhan, A. M., Jain, S. V., Salloum, M. M., Freeman, J., Khanna, R., Gannala, P., Goel, V., Jones-MacFarland, F. N., Killgore, W. D., Porreca, F., & Ibrahim, M. M. (2020). Evaluation of green light exposure on headache frequency and quality of life in migraine patients: A preliminary one-way cross-over clinical trial. Cephalalgia : an international journal of headache, 333102420956711.
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  Pharmacological management of migraine can be ineffective for some patients. We previously demonstrated that exposure to green light resulted in antinociception and reversal of thermal and mechanical hypersensitivity in rodent pain models. Given the safety of green light emitting diodes, we evaluated green light as a potential therapy in patients with episodic or chronic migraine.
• Martin, L., Porreca, F., Mata, E. I., Salloum, M., Goel, V., Gunnala, P., Killgore, W. D., Jain, S., Jones-MacFarland, F. N., Khanna, R., Patwardhan, A., & Ibrahim, M. M. (2020). Green Light Exposure Improves Pain and Quality of Life in Fibromyalgia Patients: A Preliminary One-Way Crossover Clinical Trial. Pain medicine (Malden, Mass.).
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  Fibromyalgia is a functional pain disorder in which patients suffer from widespread pain and poor quality of life. Fibromyalgia pain and its impact on quality of life are not effectively managed with current therapeutics. Previously, in a preclinical rat study, we demonstrated that exposure to green light-emitting diodes (GLED) for 8 hours/day for 5 days resulted in antinociception and reversal of thermal and mechanical hypersensitivity associated with models of injury-related pain. Given the safety of GLED and the ease of its use, our objective is to administer GLED as a potential therapy to patients with fibromyalgia.
• PhD, A. N., Rhee, J. U., Haynes, P., Chakravorty, S., Patterson, F., Killgore, W. D., Gallagher, R. A., Hale, L., Branas, C., Carrazco, N., Alfonso-Miller, P., Gehrels, J. A., & Grandner, M. A. (2020). Smoke at night and sleep worse? The associations between cigarette smoking with insomnia severity and sleep duration. Sleep health.
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  Insomnia is a clinically verified nicotine withdrawal symptom. As nicotine is a stimulant, it is plausible that smoking at night could disturb sleep more than smoking at earlier times of the day, but this remains empirically unclear. This study examined smoking status and its associations with insomnia severity and sleep duration while considering the potential role of smoking time.
• Alkozei, A., Smith, R., Waugaman, D. L., Kotzin, M. D., Bajaj, S., Killgore, W. D., Smith, R. M., Smith, R. S., & Smith, R. L. (2019). The Mediating Role of Interpretation Bias on the Relationship Between Trait Gratitude and Depressive Symptoms. International Journal of Applied Positive Psychology, 4, 135-147. doi:10.1007/s41042-019-00022-7
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  High levels of trait gratitude are associated with lower levels of depressive symptoms, but the potential mechanisms underlying this relationship have not been extensively studied. One potential explanation for this relationship is that individuals with higher levels of trait gratitude may have a more positive cognitive style, such that they interpret, attend to, and remember events in a more positive rather than negative manner. This study aimed to explore whether one aspect of a positive cognitive style, a positive interpretation bias, is a mediator in the relationship between trait gratitude and depressive symptoms. During a single visit to the lab, we asked eighty-eight individuals (41 females) to complete a measure of trait gratitude (the Gratitude Resentment and Appreciation Test [GRAT]), two measures of interpretation bias (the Sentence Completion Test for Depression [SCD], and the Ambiguous Scenarios Test for Depression [ASTD]), and a measure of depressive symptoms (the Beck Depression Inventory [BDI-II]). The results of the mediation analyses indicated that a positive interpretation bias partially explained the relationship between trait gratitude and depressive symptoms. These findings suggest that trait gratitude may reduce depressive symptoms in part through its effects on positive thinking patterns. Future longitudinal studies will be needed to elucidate the causal relationship between these variables in greater detail.
• Bajaj, S., & Killgore, W. D. (2019). Vulnerability to mood degradation during sleep deprivation is influenced by white-matter compactness of the triple-network model. NeuroImage, 202, 116123.
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  Sleep deprivation (SD) is often associated with significant shifts in mood state relative to baseline functioning. Prior work suggests that there are consistent trait-like differences among individuals in the degree to which their mood and performances are affected by sleep loss. The goal of this study was to determine the extent to which trait-like individual differences in vulnerability/resistance to mood degradation during a night of SD are dependent upon region-specific white and grey matter (WM/GM) characteristics of a triple-network model, including the default-mode network (DMN), control-execution network (CEN) and salience network (SN). Diffusion-weighted and anatomical brain data were collected from 45 healthy individuals several days prior to a 28-h overnight SD protocol. During SD, a visual analog mood scale was administered every hour from 19:15 (time point1; TP1) to 11:15 (TP17) the following morning to measure two positive and six negative mood states. Four core regions within the DMN, five within the CEN, and seven within the SN were used as regions of interest (ROIs). An index of mood resistance (IMR) was defined as the averaged differences between positive and negative mood states over 12 TPs (TP5 to TP16) relative to baseline (TP1 to TP4). For each ROI, characteristics of WM - quantitative anisotropy (QA) and mean curvature index (WM-MCI), and GM - cortical volume (CV) and GM-MCI were estimated, and used to predict IMR. WM characteristics, particularly QA, of all of regions within the DMN, and most of the regions within the CEN and SN predicted IMR during SD. In contrast, most ROIs did not show significant association between IMR and any of the GM characteristics (CV and MCI) or WM MCI. Our findings suggest that greater resilience to mood degradation induced by total SD appears to be associated with more compact axonal pathways within the DMN, CEN and SN.
• Bajaj, S., Raikes, A. C., Smith, R., Vanuk, J. R., & Killgore, W. D. (2019). The Role of Prefrontal Cortical Surface Area and Volume in Preclinical Suicidal Ideation in a Non-Clinical Sample. Frontiers in psychiatry, 10, 445.
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  Suicidal ideation (SUI) can occur in the absence of concomitant psychiatric diagnoses, and even normal levels can be problematic among individuals experiencing excess stress or lack of social support. The objective of this study was to investigate the neuroanatomical basis of SUI in non-clinical human populations who are within the normal limits of SUI, after accounting for elevated stress and perceived lack of social support. Neuroanatomical data were collected from 55 healthy individuals (mean age 30.9 ± 8.1 years, 27 females) whose depression severity levels were below the criteria. Measures of SUI, aggression, stress, non-support, and treatment rejection were collected from the treatment-consideration scales (TCS) of the Personality Assessment Inventory (PAI). Correlations between standardized SUI scores and three brain morphometry measures, vertex wise cortical thickness (CT), cortical surface area (CSA), and cortical volume (CV), were estimated for each participant, controlling for age, sex, intracranial volume, and the remaining TCS measures. We observed a significant negative association between scores on SUI and both CSA and CV (cluster-forming threshold of < 0.005, clusterwise threshold of < 0.05, corrected for multiple comparisons) within the left rostral middle frontal gyrus. Our findings suggest that greater CSA and CV within the dorsolateral prefrontal cortex are associated with reduced SUI in a non-clinical population with mild levels of stress and perceived lack of social support. Because the dorsolateral prefrontal cortex has been broadly linked to cognitive reappraisal, self-critical thoughts, and emotional regulation, greater CSA and CV within these regions may lead to better mental health by protecting healthy individuals from engaging in SUI during periods of stress and perceived insufficient social support. As our data consisted of only healthy individuals with non-clinical levels of SUI, further investigation will be necessary to explore the neural basis of SUI in populations who may be at greater risk of future suicidal behavior.
• Killgore, W. D., & Bajaj, S. (2019). Sex differences in limbic network and risk‐taking propensity in healthy individuals. Journal of Neuroscience Research, 98(2), 371-383. doi:10.1002/jnr.24504
• Li, H., Smith, S. M., Gruber, S., Lukas, S. E., Silveri, M. M., Hill, K. P., Killgore, W. D., & Nickerson, L. D. (2019). Denoising scanner effects from multimodal MRI data using linked independent component analysis. NeuroImage, 208, 116388.
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  Pooling magnetic resonance imaging (MRI) data across research studies, or utilizing shared data from imaging repositories, presents exceptional opportunities to advance and enhance reproducibility of neuroscience research. However, scanner confounds hinder pooling data collected on different scanners or across software and hardware upgrades on the same scanner, even when all acquisition protocols are harmonized. These confounds reduce power and can lead to spurious findings. Unfortunately, methods to address this problem are scant. In this study, we propose a novel denoising approach that implements a data-driven linked independent component analysis (LICA) to identify scanner-related effects for removal from multimodal MRI to denoise scanner effects. We utilized multi-study data to test our proposed method that were collected on a single 3T scanner, pre- and post-software and major hardware upgrades and using different acquisition parameters. Our proposed denoising method shows a greater reduction of scanner-related variance compared with standard GLM confound regression or ICA-based single-modality denoising. Although we did not test it here, for combining data across different scanners, LICA should prove even better at identifying scanner effects as between-scanner variability is generally much larger than within-scanner variability. Our method has great promise for denoising scanner effects in multi-study and in large-scale multi-site studies that may be confounded by scanner differences.
• Raikes, A. C., Athey, A., Alfonso-Miller, P., Killgore, W. D., & Grandner, M. A. (2019). Author response: concussion assessment tools - A possible measure of sleepiness?. Sleep medicine.
• Raikes, A. C., Athey, A., Alfonso-Miller, P., Killgore, W. D., & Grandner, M. A. (2019). Insomnia and daytime sleepiness: risk factors for sports-related concussion. Sleep medicine, 58, 66-74.
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  Poor quality and inadequate sleep are associated with impaired cognitive, motor, and behavioral components of sport performance and increased injury risk. While prior work identifies sports-related concussions as predisposing factors for poor sleep, the role of sleep as a sports-related concussion risk factor is unknown. The purpose of this study was to quantify the effect of poor sleep quality and insomnia symptoms on future sports-related concussion risk.
• Satterfield, B. C., & Killgore, W. D. (2019). Habitual sleep duration predicts caloric and macronutrient intake during sleep deprivation. Sleep health.
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  Our modern society has created two tightly linked epidemics: insufficient sleep and obesity. Although laboratory studies have established that sleep loss is associated with increased caloric intake, the critical question of how habitual at-home sleep duration influences total caloric and macronutrient intake during subsequent total sleep deprivation remains largely unexplored.
• Smith, R., Alkozei, A., & Killgore, W. D. (2019). Parameters as Trait Indicators: Exploring a Complementary Neurocomputational Approach to Conceptualizing and Measuring Trait Differences in Emotional Intelligence. Frontiers in psychology, 10, 848.
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  Current assessments of trait emotional intelligence (EI) rely on self-report inventories. While this approach has seen considerable success, a complementary approach allowing objective assessment of EI-relevant traits would provide some potential advantages. Among others, one potential advantage is that it would aid in emerging efforts to assess the brain basis of trait EI, where self-reported competency levels do not always match real-world behavior. In this paper, we review recent experimental paradigms in computational cognitive neuroscience (CCN), which allow behavioral estimates of individual differences in range of parameter values within computational models of neurocognitive processes. Based on this review, we illustrate how several of these parameters appear to correspond well to EI-relevant traits (i.e., differences in mood stability, stress vulnerability, self-control, and flexibility, among others). In contrast, although estimated objectively, these parameters do not correspond well to the optimal performance abilities assessed within competing "ability models" of EI. We suggest that adapting this approach from CCN-by treating parameter value estimates as objective trait EI measures-could (1) provide novel research directions, (2) aid in characterizing the neural basis of trait EI, and (3) offer a promising complementary assessment method.
• Vanuk, J. R., Alkozei, A., Raikes, A. C., Allen, J. J., & Killgore, W. D. (2019). Ability-Based Emotional Intelligence Is Associated With Greater Cardiac Vagal Control and Reactivity. Frontiers in human neuroscience, 13, 181.
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  Several distinct models of emotional intelligence (EI) have been developed over the past two decades. The ability model conceptualizes EI as a narrow set of interconnected, objectively measured, cognitive-emotional abilities, including the ability to perceive, manage, facilitate, and understand the emotions of the self and others. By contrast, trait or mixed models focus on subjective ratings of emotional/social competencies. Theoretically, EI is associated with neurobiological processes involved in emotional regulation and reactivity. The neurovisceral integration (NVI) model proposes a positive relationship between cardiac vagal control (CVC) and cognitive-emotional abilities similar to those encompassed by EI. The current study examined the association between CVC and EI. Because ability EI is directly tied to actual performance on emotional tasks, we hypothesized that individuals with higher ability-based EI scores would show greater levels of CVC at rest, and in response to a stressful task. Because mixed-models of EI are not linked directly to observable emotional behavior, we predicted no association with CVC. Consistent with expectations, individuals with higher levels of ability EI, but not mixed EI, had higher levels of CVC. We also found that individuals with greater levels of CVC who demonstrated reactivity to a stress induction had significantly higher EI compared to individuals that did not respond to the stress induction. Our findings support the theoretically expected overlap between constructs within the NVI model and ability EI model, however, the observed effect size was small, and the associations between EI and CVC should not be taken to indicate a causal connection. Results suggest that variance in the ability to understand emotional processes in oneself and to reason about one's visceral experience may facilitate better CVC. Future work manipulating either CVC or EI may prove informative in teasing apart the causal role driving their observed relationship.
• Alkozei, A., Haack, M., Skalamera, J., Smith, R., Satterfield, B. C., Raikes, A. C., & Killgore, W. D. (2018). Chronic sleep restriction affects the association between implicit bias and explicit social decision making. Sleep health, 4(5), 456-462.
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  Previous work suggests that sleep restriction (SR) reduces cognitive control and may increase negative implicit biases. Here we investigated whether SR might influence decision making on a social-evaluative task where individuals had to make judgments of threat based on facial photographs. Furthermore, we investigated the effect of changes in negative implicit biases as a result of sleep restriction on this decision-making task.
• Alkozei, A., Smith, R., Demers, L. A., Weber, M., Berryhill, S. M., & Killgore, W. D. (2018). Increases in Emotional Intelligence After an Online Training Program Are Associated With Better Decision-Making on the Iowa Gambling Task. Psychological reports, 33294118771705.
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  Higher levels of emotional intelligence have been associated with better inter and intrapersonal functioning. In the present study, 59 healthy men and women were randomized into either a three-week online training program targeted to improve emotional intelligence ( n = 29), or a placebo control training program targeted to improve awareness of nonemotional aspects of the environment ( n = 30). Compared to placebo, participants in the emotional intelligence training group showed increased performance on the total emotional intelligence score of the Mayer-Salovey-Caruso Emotional Intelligence Test, a performance measure of emotional intelligence, as well as subscales of perceiving emotions and facilitating thought. Moreover, after emotional intelligence training, but not after placebo training, individuals displayed the ability to arrive at optimal performance faster (i.e., they showed a faster learning rate) during an emotion-guided decision-making task (i.e., the Iowa Gambling Task). More specifically, although both groups showed similar performance at the start of the Iowa Gambling Task from pre- to posttraining, the participants in the emotional intelligence training group learned to choose more advantageous than disadvantageous decks than those in the placebo training group by the time they reached the "hunch" period of the task (i.e., the point in the task when implicit task learning is thought to have occurred). Greater total improvements in performance on the Iowa Gambling Task from pre- to posttraining in the emotional intelligence training group were also positively correlated with pre- to posttraining changes in Mayer-Salovey-Caruso Emotional Intelligence Test scores, in particular with changes in the ability to perceive emotions. The present study provides preliminary evidence that emotional intelligence can be trained with the help of an online training program targeted at adults; it also suggests that changes in emotional intelligence, as a result of such a program, can lead to improved emotion-guided decision-making.
• Bajaj, S., Dailey, N. S., Rosso, I. M., Rauch, S. L., & Killgore, W. D. (2018). Time-dependent differences in cortical measures and their associations with behavioral measures following mild traumatic brain injury. Human brain mapping.
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  There is currently a critical need to establish an improved understanding of time-dependent differences in brain structure following mild traumatic brain injury (mTBI). We compared differences in brain structure, specifically cortical thickness (CT), cortical volume (CV), and cortical surface area (CSA) in 54 individuals who sustained a recent mTBI and 33 healthy controls (HCs). Individuals with mTBI were split into three groups, depending on their time since injury. By comparing structural measures between mTBI and HC groups, differences in CT reflected cortical thickening within several areas following 0-3 (time-point, TP1) and 3-6 months (TP2) post-mTBI. Compared with the HC group, the mTBI group at TP2 showed lower CSA within several areas. Compared with the mTBI group at TP2, the mTBI group during the most chronic stage (TP3: 6-18 months post-mTBI) showed significantly higher CSA in several areas. All the above reported differences in CT and CSA were significant at a cluster-forming p < .01 (corrected for multiple comparisons). We also found that in the mTBI group at TP2, CT within two clusters (i.e., the left rostral middle frontal gyrus (L. RMFG) and the right postcentral gyrus (R. PostCG)) was negatively correlated with basic attention abilities (L. RMFG: r = -.41, p = .05 and R. PostCG: r = -.44, p = .03). Our findings suggest that alterations in CT and associated neuropsychological assessments may be more prominent during the early stages of mTBI. However, alterations in CSA may reflect compensatory structural recovery during the chronic stages of mTBI.
• Bajaj, S., Raikes, A., Smith, R., Dailey, N. S., Alkozei, A., Vanuk, J. R., & Killgore, W. D. (2018). The Relationship Between General Intelligence and Cortical Structure in Healthy Individuals. Neuroscience, 388, 36-44.
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  Considerable work in recent years has examined the relationship between cortical thickness (CT) and general intelligence (IQ) in healthy individuals. It is not known whether specific IQ variables (i.e., perceptual reasoning [PIQ], verbal comprehension IQ [VIQ], and full-scale IQ [FSIQ]) are associated with multiple cortical measures (i.e., CT, cortical volume (CV), cortical surface area (CSA) and cortical gyrification (CG)) within the same individuals. Here we examined the association between these neuroimaging metrics and IQ in 56 healthy adults. At a cluster-forming threshold (CFT) of p 
• Dailey, N. S., Smith, R., Bajaj, S., Alkozei, A., Gottschlich, M. K., Raikes, A. C., Satterfield, B. C., & Killgore, W. D. (2018). Elevated Aggression and Reduced White Matter Integrity in Mild Traumatic Brain Injury: A DTI Study. Frontiers in behavioral neuroscience, 12, 118.
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  Mild traumatic brain injury (mTBI) remains the most commonly reported head injury in the United States, and is associated with a wide range of post-concussive symptoms including physical, cognitive and affective impairments. Elevated aggression has been documented in mTBI; however, the neural mechanisms associated with aggression at the chronic stage of recovery remain poorly understood. In the present study, we investigated the association between white matter integrity and aggression in mTBI using diffusion tensor imaging (DTI). Twenty-six age-matched adults participated in the study, including 16 healthy controls (HCs) and 10 individuals in the chronic stage of recovery (either 6-months or 12 months post-mTBI). Psychological measures of aggression included the Buss-Perry Aggression Questionnaire and the Personality Assessment Inventory (PAI). Axonal pathways implicated in affective processing were studied, including the corpus callosum, anterior thalamic radiation, cingulum and uncinate fasciculus, and measures of white matter integrity included fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). We found that adults with mTBI in the chronic stage of recovery had higher levels aggression. Individuals with mTBI also had greater RD in the corpus callosum compared to HCs, indicating reduced fiber integrity. Furthermore, we observed a significant association between reduced white matter integrity in the corpus callosum and greater aggression. Our findings provide additional evidence for underlying neuroanatomical mechanisms of aggression, although future research will be necessary to characterize the specific relationship between aggression and the white matter pathways we identified.
• Dailey, N. S., Smith, R., Vanuk, J. R., Raikes, A. C., & Killgore, W. D. (2018). Resting-state functional connectivity as a biomarker of aggression in mild traumatic brain injury. Neuroreport, 29(16), 1413-1417.
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  Mild traumatic brain injury (mTBI) can alter the structure of the brain and result in a range of symptoms, including elevated aggression. Neurological damage associated with mTBI is traditionally viewed as transient, yet a growing number of studies suggest long-lasting psychological and neurological changes following mTBI. However, research examining the neural basis of emotion processing in the chronic stage of mTBI recovery remains sparse. In the current study, we utilized resting state functional MRI to explore the association between default mode network connectivity and aggression in 17 healthy controls and 17 adults at least 6 months post-mTBI. The association between within-network connectivity and aggression was examined using general linear models, controlling for the effects of depression. Increased connectivity between the right hippocampus and midcingulate cortex was associated with elevated aggression in adults with mTBI, but not in healthy controls. The results provide evidence for a link between intrinsic functional network disruptions and the manifestation of postconcussive symptoms within chronic stages of recovery following mTBI. These findings expand upon the current research, providing evidence for the use of resting state functional connectivity as a potential biomarker of postconcussive aggression in chronic mTBI.
• Killgore, W. D., Kent, H. C., Knight, S. A., & Alkozei, A. (2018). Changes in morning salivary melatonin correlate with prefrontal responses during working memory performance. Neuroreport, 29(6), 488-494.
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  Humans demonstrate a circadian rhythm of melatonin production that closely tracks the daily light/dark cycle, with profound increases in circulating levels during the night-time and nearly nonexistent levels during daylight hours. Although melatonin is known to play a role in preparing the brain and body for sleep, its effects on cognition and brain function are not well understood. We hypothesized that declines in morning melatonin would be associated with increased functional activation within cortical regions involved in alertness, attention, and executive function. We measured the change in salivary melatonin from mid-morning to late-morning in 26 healthy young adults who were also exposed to a 30-min period of blue or amber light followed by functional MRI during a working memory task (N-back). Brain activation was regressed on the change in melatonin scores from the mid-morning to late-morning saliva samples and the role of light exposure was also assessed. Although overall melatonin levels did not change significantly over the morning at the group level, individual declines in salivary melatonin were associated with significant increases in activation within the left dorsomedial and right inferior lateral prefrontal cortex during the 2-back condition (P
• McConnell, M. H., Killgore, W. D., & O'Connor, M. F. (2018). Yearning predicts subgenual anterior cingulate activity in bereaved individuals. Heliyon, 4(10), e00852.
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  Complicated grief, or persistent complex bereavement disorder, is a condition that affects approximately 10% of bereaved individuals and is marked by intense longing and yearning for the deceased. Little is known about the neurocognitive mechanisms contributing to this syndrome, but previous research suggests that reward pathways in the brain may play a role. Twenty-five older adults were categorized based on grief severity into one of three groups: complicated grief (CG), non-complicated grief (NCG) and non-bereaved married controls (NB). Neural activation was examined using fMRI while participants viewed a countdown on the screen (anticipation) followed by a photo of their (living or deceased) spouse. There was no significantly differential activation between the three groups for the spouse v. stranger photo contrast, nor for anticipation period v. spouse photo. Post-hoc analyses were conducted using self-reported yearning scores as a regressor across all bereaved participants, which revealed that greater symptoms of yearning predicted greater activation in the subgenual anterior cingulate cortex (sgACC). Given the small sample size, the results should be considered preliminary and in need of replication, but may suggest a more nuanced, transdiagnostic role of the sgACC. This region of the brain has been previously linked to depression and suggests that symptoms of yearning may present an opportune place to intervene to improve outcomes in CG.
• Raikes, A. C., & Killgore, W. D. (2018). Potential for the development of light therapies in mild traumatic brain injury. Concussion (London, England), 3(3), CNC57.
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  Light affects almost all aspects of human physiological functioning, including circadian rhythms, sleep-wake regulation, alertness, cognition and mood. We review the existing relevant literature on the effects of various wavelengths of light on these major domains, particularly as they pertain to recovery from mild traumatic brain injuries. Evidence suggests that light, particularly in the blue wavelengths, has powerful alerting, cognitive and circadian phase shifting properties that could be useful for treatment. Other wavelengths, such as red and green may also have important effects that, if targeted appropriately, might also be useful for facilitating recovery. Despite the known effects of light, more research is needed. We recommend a personalized medicine approach to the use of light therapy as an adjunctive treatment for patients recovering from mild traumatic brain injury.
• Raikes, A. C., Bajaj, S., Dailey, N. S., Smith, R. S., Alkozei, A., Satterfield, B. C., & Killgore, W. D. (2018). Diffusion Tensor Imaging (DTI) Correlates of Self-Reported Sleep Quality and Depression Following Mild Traumatic Brain Injury. Frontiers in neurology, 9, 468.
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  Mild traumatic brain injuries (mTBIs) are a significant social, sport, and military health issue. In spite of advances in the clinical management of these injuries, the underlying pathophysiology is not well-understood. There is a critical need to advance objective biomarkers, allowing the identification and tracking of the long-term evolution of changes resulting from mTBI. Diffusion-weighted imaging (DWI) allows for the assessment of white-matter properties in the brain and shows promise as a suitable biomarker of mTBI pathophysiology. 34 individuals within a year of an mTBI (age: 24.4 ± 7.4) and 18 individuals with no history of mTBI (age: 23.2 ± 3.4) participated in this study. Participants completed self-report measures related to functional outcomes, psychological health, post-injury symptoms, and sleep, and underwent a neuroimaging session that included DWI. Whole-brain white matter was skeletonized using tract-based spatial statistics (TBSS) and compared between groups as well as correlated within-group with the self-report measures. There were no statistically significant anatomical differences between the two groups. After controlling for time since injury, fractional anisotropy (FA) demonstrated a negative correlation with sleep quality scores (higher FA was associated with better sleep quality) and increasing depressive symptoms in the mTBI participants. Conversely, mean (MD) and radial diffusivity (RD) demonstrated positive correlations with sleep quality scores (higher RD was associated with worse sleep quality) and increasing depressive symptoms. These correlations were observed bilaterally in the internal capsule (anterior and posterior limbs), corona radiata (anterior and superior), fornix, and superior fronto-occipital fasciculi. The results of this study indicate that the clinical presentation of mTBI, particularly with respect to depression and sleep, is associated with reduced white-matter integrity in multiple areas of the brain, even after controlling for time since injury. These areas are generally associated not only with sleep and emotion regulation but also cognition. Consequently, the onset of depression and sleep dysfunction as well as cognitive impairments following mTBI may be closely related to each other and to white-matter integrity throughout the brain.
• Raikes, A. C., Satterfield, B. C., & Killgore, W. D. (2018). Evidence of actigraphic and subjective sleep disruption following mild traumatic brain injury. Sleep medicine, 54, 62-69.
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  Mild traumatic brain injuries (mTBI) are frequently associated with long-term, self-reported sleep disruption. Objective corroboration of these self-reports is sparse and limited by small sample sizes. The purpose of this study was to report on actigraphically-measured sleep outcomes in individuals with and without a history of recent mTBI in two U.S. cities (Boston, MA and Tucson, AZ).
• Satterfield, B. C., Raikes, A. C., & Killgore, W. D. (2018). Rested-Baseline Responsivity of the Ventral Striatum Is Associated With Caloric and Macronutrient Intake During One Night of Sleep Deprivation. Frontiers in psychiatry, 9, 749.
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  Sleep loss contributes to obesity through a variety of mechanisms, including neuroendocrine functioning, increased hunger, and increased food intake. Additionally, sleep loss alters functional activation within brain regions associated with reward and behavioral control. However, it remains unknown whether individual differences in baseline neural functioning can predict eating behaviors during total sleep deprivation (TSD). We used functional magnetic resonance imaging (fMRI) to test the hypothesis that individuals with increased baseline responsiveness within reward regions are more vulnerable to TSD-induced overeating. = 45 subjects completed several fMRI scans during a single pre-TSD session that included performance on the Multi-Source Interference Task (MSIT) and the back task. Subjects returned to the laboratory for an overnight TSD session, during which they were given access to 10,900 kcal of food. Leftover food and packaging were collected every 6 h (00:00, 06:00, and 12:00) to measure total food consumption. Subjects reported sleepiness every hour and performed a food rating task every 3 h. Functional activation within the ventral striatum during the MSIT and -back positively correlated with total caloric and carbohydrate intake during the final 6 h (06:00-12:00) of TSD. Activation within the middle and superior temporal gyri during the MSIT also correlated with total carbohydrates consumed. Food consumption did not correlate with subjective sleepiness, hunger, or food desire. Individual differences in neural activity of reward processing areas (i.e., nucleus accumbens) sleep deprivation are associated with an individual's propensity to overeat during subsequent sleep deprivation. This suggests that individual differences within reward processing pathways are potential key factors in sleep loss related overeating. Sleep loss and obesity are tightly linked. Both phenomena have been associated with increased neural activation in regions associated with reward, inhibitory control, and disrupted dopamine signaling. Elevated baseline reward sensitivity in the ventral striatum appears to be further compounded by sleep deprivation induced dysfunction in the reward neurocircuitry, increasing the likelihood of overeating. Our findings suggest that large individual differences in baseline responsiveness of hedonic reward pathways may modulate the association between sleep loss and obesity.
• Smith, R., Alkozei, A., Bao, J., & Killgore, W. D. (2018). Successful Goal-Directed Memory Suppression is Associated With Increased Inter-Hemispheric Coordination Between Right and Left Frontoparietal Control Networks. Psychological reports, 121(1), 93-111.
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  The neural basis of suppressing conscious access to one's own memories has recently received considerable attention, with several studies suggesting this process engages frontal-parietal cognitive control regions. However, researchers to date have not examined the way right and left hemisphere cognitive control networks coordinate with one another to accomplish this. We had 48 participants (25 female) complete a Think/No Think (T/NT) task for memories of emotionally unpleasant visual scenes while undergoing functional magnetic resonance imaging. We used generalized psychophysiologic interaction analyses to examine functional connectivity between right and left hemisphere frontal-parietal regions during memory suppression. Participants who were better at memory suppression, as assessed by greater numbers of forgotten memories in the NT than T conditions, also showed greater functional connectivity between multiple right and left hemisphere control regions. This suggests that individual differences in memory suppression ability may be partially explained by differences in task-specific inter-hemispheric coordination.
• Smith, R., Alkozei, A., Killgore, W. D., & Lane, R. D. (2018). Nested positive feedback loops in the maintenance of major depression: An integration and extension of previous models. Brain, behavior, and immunity, 67, 374-397.
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  Several theories of Major Depressive Disorder (MDD) have previously been proposed, focusing largely on either a psychological (i.e., cognitive/affective), biological, or neural/computational level of description. These theories appeal to somewhat distinct bodies of work that have each highlighted separate factors as being of considerable potential importance to the maintenance of MDD. Such factors include a range of cognitive/attentional information-processing biases, a range of structural and functional brain abnormalities, and also dysregulation within the autonomic, endocrine, and immune systems. However, to date there have been limited efforts to integrate these complimentary perspectives into a single multi-level framework. Here we review previous work in each of these MDD research domains and illustrate how they can be synthesized into a more comprehensive model of how a depressive episode is maintained. In particular, we emphasize how plausible (but insufficiently studied) interactions between the various MDD-related factors listed above can lead to a series of nested positive feedback loops, which are each capable of maintaining an individual in a depressive episode. We also describe how these different feedback loops could be active to different degrees in different individual cases, potentially accounting for heterogeneity in both depressive symptoms and treatment response. We conclude by discussing how this integrative model might extend understanding of current treatment mechanisms, and also potentially guide the search for markers to inform treatment selection in individual cases.
• Smith, R., Bajaj, S., Dailey, N. S., Alkozei, A., Smith, C., Sanova, A., Lane, R. D., & Killgore, W. D. (2018). Greater cortical thickness within the limbic visceromotor network predicts higher levels of trait emotional awareness. Consciousness and cognition, 57, 54-61.
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  Previous studies of trait emotional awareness (EA) have not yet examined whether differences in cortical structure might account for differences in EA. Based on previous research on the relationship between EA and both emotion conceptualization and visceromotor control processes, we tested two hypotheses in a sample of 26 healthy participants: that higher EA would be predicted by greater cortical thickness within (1) regions of the default mode network (DMN; linked with conceptualization processes), and/or (2) regions of the limbic network (linked with affect generation and visceromotor control processes). A non-significant correlation was found between EA and cortical thickness in the DMN. In contrast, a significant positive correlation was observed between EA and cortical thickness within the limbic network. These findings suggest that the structural integrity of cortical regions involved in the generation of affective bodily reactions may play a more important role in explaining differences in EA than previously thought.
• Smith, R., Killgore, W. D., Alkozei, A., & Lane, R. D. (2018). A neuro-cognitive process model of emotional intelligence. Biological psychology, 139, 131-151.
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  The construct of emotional intelligence (EI) broadly reflects the idea that individuals differ in their disposition/ability to adaptively generate, recognize, understand, and regulate the emotions of self and others. However, while the neural processes underlying such differences have begun to receive investigation, no brain-based model of EI has yet been proposed to help guide the design and interpretation of neuroimaging research in this area. In this article, we propose a neural model of EI to fill this need. This model incorporates recent insights from emotion theory, computational neuroscience, and large-scale network models of brain function. It also highlights several domain general processes - including those underlying conceptualization, automatic attention, habit formation, and cognitive control - that offer plausible targets for improving EI with training. Our model offers considerable promise in advancing understanding of intelligent emotional functioning and in guiding future neuroscience research on EI.
• Smith, R., Lane, R. D., Alkozei, A., Bao, J., Smith, C., Sanova, A., Nettles, M., & Killgore, W. D. (2018). The role of medial prefrontal cortex in the working memory maintenance of one's own emotional responses. Scientific reports, 8(1), 3460.
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  The role of medial prefrontal cortex (MPFC) in maintaining emotional information within working memory (WM) remains insufficiently investigated - with some studies suggesting this process activates MPFC and others suggesting its activity is suppressed. To reconcile these different results, we asked 26 healthy participants to complete a WM task involving the maintenance of emotional content (EWM), visual content (VWM), or no content ("rest") after exposure to emotion-provoking images. We also assessed individual differences in emotional awareness (EA). We observed that dorsal MPFC was more active during EWM than VWM; further, relative to the rest condition, both of these WM conditions involved suppression of ventral MPFC. We also observed that the dorsal anterior cingulate subregion of dorsal MPFC was positively associated with EA. We discuss how these results may be able to reconcile the findings of previous EWM studies, and extend understanding of the relationship between MPFC, EA, and WM.
• Smith, R., Lane, R. D., Sanova, A., Alkozei, A., Smith, C., & Killgore, W. D. (2018). Common and Unique Neural Systems Underlying the Working Memory Maintenance of Emotional vs. Bodily Reactions to Affective Stimuli: The Moderating Role of Trait Emotional Awareness. Frontiers in human neuroscience, 12, 370.
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  Many leading theories suggest that the neural processes underlying the experience of one's own emotional reactions partially overlap with those underlying bodily perception (i.e., interoception, somatosensation, and proprioception). However, the goal-directed maintenance of one's own emotions in working memory (EWM) has not yet been compared to WM maintenance of one's own bodily reactions (BWM). In this study, we contrasted WM maintenance of emotional vs. bodily reactions to affective stimuli in 26 healthy individuals while they underwent functional magnetic resonance imaging. Specifically, we examined the a priori hypothesis that individual differences in trait emotional awareness (tEA) would lead to greater differences between these two WM conditions within medial prefrontal cortex (MPFC). We observed that MPFC activation during EWM (relative to BWM) was positively associated with tEA. Whole-brain analyses otherwise suggested considerable similarity in the neural activation patterns associated with EWM and BWM. In conjunction with previous literature, our findings not only support a central role of body state representation/maintenance in EWM, but also suggest greater engagement of MPFC-mediated conceptualization processes during EWM in those with higher tEA.
• Smith, R., Sanova, A., Alkozei, A., Lane, R. D., & Killgore, W. D. (2018). Higher levels of trait emotional awareness are associated with more efficient global information integration throughout the brain: a graph-theoretic analysis of resting state functional connectivity. Social cognitive and affective neuroscience, 13(7), 665-675.
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  Previous studies have suggested that trait differences in emotional awareness (tEA) are clinically relevant, and associated with differences in neural structure/function. While multiple leading theories suggest that conscious awareness requires widespread information integration across the brain, no study has yet tested the hypothesis that higher tEA corresponds to more efficient brain-wide information exchange. Twenty-six healthy volunteers (13 females) underwent a resting state functional magnetic resonance imaging scan, and completed the Levels of Emotional Awareness Scale (LEAS; a measure of tEA) and the Wechsler Abbreviated Scale of Intelligence (WASI-II; a measure of general intelligence quotient [IQ]). Using a whole-brain (functionally defined) region of interest (ROI) atlas, we computed several graph theory metrics to assess the efficiency of brain-wide information exchange. After statistically controlling for differences in age, gender and IQ, we first observed a significant relationship between higher LEAS scores and greater average degree (i.e. overall whole-brain network density). When controlling for average degree, we found that higher LEAS scores were also associated with shorter average path lengths across the collective network of all included ROIs. These results jointly suggest that individuals with higher tEA display more efficient global information exchange throughout the brain. This is consistent with the idea that conscious awareness requires global accessibility of represented information.
• Smith, R., Weihs, K. L., Alkozei, A., Killgore, W. D., & Lane, R. D. (2018). An embodied neurocomputational framework for organically integrating biopsychosocial processes: An application to the role of social support in health and disease. Psychosomatic medicine.
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  Two distinct perspectives - typically referred to as the biopsychosocial and biomedical models - currently guide clinical practice. While the role of psychosocial factors in contributing to physical and mental health outcomes is widely recognized, the biomedical model remains dominant. This is due in part to 1) the largely non-mechanistic focus of biopsychosocial research, and 2) the lack of specificity it currently offers in guiding clinicians to focus on social, psychological, and/or biological factors in individual cases. In this article, our objective is to provide an evidence-based and theoretically sophisticated mechanistic model capable of organically integrating biopsychosocial processes.
• Webb, C. A., DelDonno, S., & Killgore, W. D. (2014). The role of cognitive versus emotional intelligence in Iowa Gambling Task performance: What's emotion got to do with it?. Intelligence, 44, 112-119.
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  Debate persists regarding the relative role of cognitive versus emotional processes in driving successful performance on the widely used Iowa Gambling Task (IGT). From the time of its initial development, patterns of IGT performance were commonly interpreted as primarily reflecting implicit, emotion-based processes. Surprisingly, little research has tried to directly compare the extent to which measures tapping relevant cognitive versus emotional competencies predict IGT performance in the same study. The current investigation attempts to address this question by comparing patterns of associations between IGT performance, cognitive intelligence (Wechsler Abbreviated Scale of Intelligence; WASI) and three commonly employed measures of emotional intelligence (EI; Mayer-Salovey-Caruso Emotional Intelligence Test, MSCEIT; Bar-On Emotional Quotient Inventory, EQ-i; Self-Rated Emotional Intelligence Scale, SREIS). Results indicated that IGT performance was more strongly associated with cognitive, than emotional, intelligence. To the extent that the IGT indeed mimics "real-world" decision-making, our findings, coupled with the results of existing research, may highlight the role of deliberate, cognitive capacities over implicit, emotional processes in contributing to at least some domains of decision-making relevant to everyday life.
• Webb, C. A., Olson, E. A., Killgore, W. D., Pizzagalli, D. A., Rauch, S. L., & Rosso, I. M. (2018). Rostral Anterior Cingulate Cortex Morphology Predicts Treatment Response to Internet-Based Cognitive Behavioral Therapy for Depression. Biological psychiatry. Cognitive neuroscience and neuroimaging, 3(3), 255-262.
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  Rostral and subgenual anterior cingulate cortex (rACC and sgACC) activity and, to a lesser extent, volume have been shown to predict depressive symptom improvement across different antidepressant treatments. This study extends prior work by examining whether rACC and/or sgACC morphology predicts treatment response to Internet-based cognitive behavioral therapy (iCBT) for major depressive disorder. This is the first study to examine neural predictors of response to iCBT.
• Alkozei, A., Killgore, W. D., Smith, R., Dailey, N. S., Bajaj, S., & Haack, M. (2017). Chronic Sleep Restriction Increases Negative Implicit Attitudes Toward Arab Muslims. Scientific reports, 7(1), 4285.
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  Chronic sleep restriction is a common experience; and while it has negative physiological effects, little is known about how it affects human behavior. To date, no study has investigated whether chronic sleep restriction can influence implicit attitudes (e.g., towards a race). Here, in a randomized, counterbalanced crossover design, we subjected participants to 3 weeks of chronic sleep restriction in the lab (i.e., 3 weekly cycles of 5 nights of 4 hours of sleep per night followed by 2 nights of 8 hours of sleep) and found evidence for an increased negative implicit bias towards Arab Muslims. No indicators of an implicit bias were found in these same individuals when they were rested (during a counterbalanced 3-week period of 8 hours time in bed per night). These findings suggest that chronic sleep restriction may "unmask" implicit racial or ethnic biases that are otherwise inhibited when in a rested state. Because chronic sleep restriction is prevalent among many occupations that routinely interact with ethnic minorities in potentially high-conflict situations (e.g., police officers), it is critical to consider the role that restricted sleep may play in exacerbating negative implicit attitudes and their potential for provoking unintentional and potentially harmful behavioral consequences.
• Alkozei, A., Killgore, W. D., Smith, R., Dailey, N. S., Bajaj, S., Raikes, A. C., & Haack, M. (2017). Chronic sleep restriction differentially affects implicit biases toward food among men and women: preliminary evidence. Journal of sleep research.
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  Chronic sleep restriction and obesity are two major public health concerns. This study investigated how chronic sleep restriction changes implicit attitudes towards low- and high-calorie foods. In a randomized, counterbalanced cross-over design, 17 participants (eight females, nine males) underwent two laboratory testing sessions where they were either sleep-restricted for 3 weeks (i.e. underwent three weekly cycles of 5 nights of 4 h of sleep followed by 2 nights of 8 h of sleep opportunity) or received 3 weeks of control sleep (i.e. 8 h of sleep opportunity per night for 3 weeks). There was evidence for a significant sleep condition x sex interaction (F(1, 20)  = 4.60, P = 0.04). After chronic sleep restriction, men showed a trend towards a significant decrease in their implicit attitudes favouring low-calorie foods (P = 0.08), whereas women did not show a significant change (P = 0.16). Men may be at increased risk of weight gain when sleep-deprived due to a reduced bias towards low-calorie foods.
• Alkozei, A., Smith, R., Dailey, N. S., Bajaj, S., & Killgore, W. D. (2017). Acute exposure to blue wavelength light during memory consolidation improves verbal memory performance. PloS one, 12(9), e0184884.
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  Acute exposure to light within the blue wavelengths has been shown to enhance alertness and vigilance, and lead to improved speed on reaction time tasks, possibly due to activation of the noradrenergic system. It remains unclear, however, whether the effects of blue light extend beyond simple alertness processes to also enhance other aspects of cognition, such as memory performance. The aim of this study was to investigate the effects of a thirty minute pulse of blue light versus placebo (amber light) exposure in healthy normally rested individuals in the morning during verbal memory consolidation (i.e., 1.5 hours after memory acquisition) using an abbreviated version of the California Verbal Learning Test (CVLT-II). At delayed recall, individuals who received blue light (n = 12) during the consolidation period showed significantly better long-delay verbal recall than individuals who received amber light exposure (n = 18), while controlling for the effects of general intelligence, depressive symptoms and habitual wake time. These findings extend previous work demonstrating the effect of blue light on brain activation and alertness to further demonstrate its effectiveness at facilitating better memory consolidation and subsequent retention of verbal material. Although preliminary, these findings point to a potential application of blue wavelength light to optimize memory performance in healthy populations. It remains to be determined whether blue light exposure may also enhance performance in clinical populations with memory deficits.
• Alkozei, A., Smith, R., Kotzin, M. D., Waugaman, D. L., & Killgore, W. D. (2017). The Association Between Trait Gratitude and Self-Reported Sleep Quality Is Mediated by Depressive Mood State. Behavioral sleep medicine, 1-9.
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  It has been shown that higher levels of trait gratitude are associated with better self-reported sleep quality, possibly due to differences in presleep cognitions. However previous studies have not taken into account the role of depressive symptoms in this relationship.
• Bajaj, S., Alkozei, A., Dailey, N. S., & Killgore, W. D. (2017). Brain Aging: Uncovering Cortical Characteristics of Healthy Aging in Young Adults. Frontiers in aging neuroscience, 9, 412.
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  Despite extensive research in the field of aging neuroscience, it still remains unclear whether age related cortical changes can be detected in different functional networks of younger adults and whether these networks respond identically to healthy aging. We collected high-resolution brain anatomical data from 56 young healthy adults (mean age = 30.8 ± 8.1 years, 29 males). We performed whole brain parcellation into seven functional networks, including visual, somatomotor, dorsal attention, ventral attention, limbic, frontoparietal and default mode networks. We estimated intracranial volume (ICV) and averaged cortical thickness (CT), cortical surface area (CSA) and cortical volume (CV) over each hemisphere as well as for each network. Averaged cortical measures over each hemisphere, especially CT and CV, were significantly lower in older individuals compared to younger ones (one-way ANOVA, p < 0.05, corrected for multiple comparisons). There were negative correlations between age and averaged CT and CV over each hemisphere (p < 0.05, corrected for multiple comparisons) as well as between age and ICV (p = 0.05). Network level analysis showed that age was negatively correlated with CT for all functional networks (p < 0.05, corrected for multiple comparisons), apart from the limbic network. While age was unrelated to CSA, it was negatively correlated with CV across several functional networks (p < 0.05, corrected for multiple comparisons). We also showed positive associations between CV and CT and between CV and CSA for all networks (p < 0.05, corrected for multiple comparisons). We interpret the lack of association between age and CT of the limbic network as evidence that the limbic system may be particularly resistant to age-related declines during this period of life, whereas the significant age-related declines in averaged CT over each hemisphere as well as in all other six networks suggests that CT may serve as a reliable biomarker to capture the effect of normal aging. Due to the simultaneous dependence of CV on CT and CSA, CV was unable to identify such effects of normal aging consistently for the other six networks, but there were negative associations observed between age and averaged CV over each hemisphere as well as between age and ICV. Our findings suggest that the identification of early cortical changes within various functional networks during normal aging might be useful for predicting the effect of aging on the efficiency of functional performance even during early adulthood.
• Bajaj, S., Vanuk, J. R., Smith, R., Dailey, N. S., & Killgore, W. D. (2017). Blue-Light Therapy following Mild Traumatic Brain Injury: Effects on White Matter Water Diffusion in the Brain. Frontiers in neurology, 8, 616.
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  Mild traumatic brain injury (mTBI) is a common and often inconspicuous wound that is frequently associated with chronic low-grade symptoms and cognitive dysfunction. Previous evidence suggests that daily blue wavelength light therapy may be effective at reducing fatigue and improving sleep in patients recovering from mTBI. However, the effects of light therapy on recovering brain structure remain unexplored. In this study, we analyzed white matter diffusion properties, including generalized fractional anisotropy, and the quantity of water diffusion in isotropic (i.e., isotropic diffusion) and anisotropic fashion (i.e., quantitative anisotropy, QA) for fibers crossing 11 brain areas known to be significantly affected following mTBI. Specifically, we investigated how 6 weeks of daily morning blue light exposure therapy (compared to an amber-light placebo condition) impacted changes in white matter diffusion in individuals with mTBI. We observed a significant impact of the blue light treatment (relative to the placebo) on the amount of water diffusion (QA) for multiple brain areas, including the corpus callosum, anterior corona radiata, and thalamus. Moreover, many of these changes were associated with improvements in sleep latency and delayed memory. These findings suggest that blue wavelength light exposure may serve as one of the potential non-pharmacological treatments for facilitating structural and functional recovery following mTBI; they also support the use of QA as a reliable neuro-biomarker for mTBI therapies.
• Goel, N., Taylor, D., Abel, T., Pearson-leary, J., Bhatnagar, S., & Killgore, W. D. (2017). 0022 MICRORNAS ARE CROSS-SPECIES MARKERS OF SLEEP LOSS IN HUMANS AND RATS. Sleep, 40(suppl_1), A8-A8. doi:10.1093/sleepj/zsx050.021
• Killgore, W. D., Alkozei, A., Smith, R., & Bao, J. (2017). Successful Goal-Directed Memory Suppression is Associated With Increased Inter-Hemispheric Coordination Between Right and Left Frontoparietal Control Networks. Psychological Reports, 121(1), 93-111. doi:10.1177/0033294117723018
• Killgore, W. D., Balkin, T. J., Yarnell, A. M., & Capaldi, V. F. (2017). Sleep deprivation impairs recognition of specific emotions. Neurobiology of sleep and circadian rhythms, 3, 10-16.
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  Emotional processing is particularly sensitive to sleep deprivation, but research on the topic has been limited and prior studies have generally evaluated only a circumscribed subset of emotion categories. Here, we evaluated the effects of one night of sleep deprivation and a night of subsequent recovery sleep on the ability to identify the six most widely agreed upon basic emotion categories (happiness, surprise, fear, sadness, disgust, anger). Healthy adults (29 males; 25 females) classified a series of 120 standard facial expressions that were computer morphed with their most highly confusable expression counterparts to create continua of expressions that differed in discriminability between emotion categories (e.g., combining 70% happiness+30% surprise; 90% surprise+10% fear). Accuracy at identifying the dominant emotion for each morph was assessed after a normal night of sleep, again following a night of total sleep deprivation, and finally after a night of recovery sleep. Sleep deprivation was associated with significantly reduced accuracy for identifying the expressions of happiness and sadness in the morphed faces. Gender differences in accuracy were not observed and none of the other emotions showed significant changes as a function of sleep loss. Accuracy returned to baseline after recovery sleep. Findings suggest that sleep deprivation adversely affects the recognition of subtle facial cues of happiness and sadness, the two emotions that are most relevant to highly evolved prosocial interpersonal interactions involving affiliation and empathy, while the recognition of other more primitive survival-oriented emotional face cues may be relatively robust against sleep loss.
• Killgore, W. D., Smith, R., Olson, E. A., Weber, M., Rauch, S. L., & Nickerson, L. D. (2017). Emotional intelligence is associated with connectivity within and between resting state networks. Social cognitive and affective neuroscience, 12(10), 1624-1636.
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  Emotional intelligence (EI) is defined as an individual's capacity to accurately perceive, understand, reason about, and regulate emotions, and to apply that information to facilitate thought and achieve goals. Although EI plays an important role in mental health and success in academic, professional and social realms, the neurocircuitry underlying this capacity remains poorly characterized, and no study to date has yet examined the relationship between EI and intrinsic neural network function. Here, in a sample of 54 healthy individuals (28 women, 26 men), we apply independent components analysis (ICA) with dual regression to functional magnetic resonance imaging (fMRI) data acquired while subjects were resting in the scanner to investigate brain circuits (intrinsic resting state networks) whose activity is associated with greater self-reported (i.e. Trait) and objectively measured (i.e. Ability) EI. We show that higher Ability EI, but not Trait EI, is associated with stronger negatively correlated spontaneous fMRI signals between the basal ganglia/limbic network (BGN) and posterior default mode network (DMN), and regions involved in emotional processing and regulation. Importantly, these findings suggest that the functional connectivity within and between intrinsic networks associated with mentation, affective regulation, emotion processing, and reward are strongly related to ability EI.
• Marin, M. F., Zsido, R. G., Song, H., Lasko, N. B., Killgore, W. D., Rauch, S. L., Simon, N. M., & Milad, M. R. (2017). Skin Conductance Responses and Neural Activations During Fear Conditioning and Extinction Recall Across Anxiety Disorders. JAMA psychiatry, 74(6), 622-631.
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  The fear conditioning and extinction neurocircuitry has been extensively studied in healthy and clinical populations, with a particular focus on posttraumatic stress disorder. Despite significant overlap of symptoms between posttraumatic stress disorder and anxiety disorders, the latter has received less attention. Given that dysregulated fear levels characterize anxiety disorders, examining the neural correlates of fear and extinction learning may shed light on the pathogenesis of underlying anxiety disorders.
• Pisner, D. A., Smith, R., Alkozei, A., Klimova, A., & Killgore, W. D. (2017). Highways of the emotional intellect: white matter microstructural correlates of an ability-based measure of emotional intelligence. Social neuroscience, 12(3), 253-267.
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  Individuals differ in their ability to understand emotional information and apply that understanding to make decisions and solve problems effectively - a construct known as Emotional Intelligence (EI). While considerable evidence supports the importance of EI in social and occupational functioning, the neural underpinnings of this capacity are relatively unexplored. We used Tract-Based Spatial Statistics (TBSS) to determine the white matter correlates of EI as measured by the ability-based Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). Participants included 32 healthy adults (16 men; 16 women), aged 18-45 years. White matter integrity in key tracts was positively correlated with the Strategic Area branches of the MSCEIT (Understanding Emotions and Managing Emotions), but not the Experiential branches (Perceiving and Facilitating Emotions). Specifically, the Understanding Emotions branch was associated with greater fractional anisotropy (FA) within somatosensory and sensory-motor fiber bundles, particularly those of the left superior longitudinal fasciculus and corticospinal tract. Managing Emotions was associated with greater FA within frontal-affective association tracts including the anterior forceps and right uncinate fasciculus, along with frontal-parietal cingulum and interhemispheric corpus callosum tracts. These findings suggest that specific components of EI are directly related to the structural microarchitecture of major axonal pathways.
• Rosso, I. M., Killgore, W. D., Olson, E. A., Webb, C. A., Fukunaga, R., Auerbach, R. P., Gogel, H., Buchholz, J. L., & Rauch, S. L. (2017). Internet-based cognitive behavior therapy for major depressive disorder: A randomized controlled trial. Depression and anxiety, 34(3), 236-245.
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  Prior research has shown that the Sadness Program, a technician-assisted Internet-based cognitive behavioral therapy (iCBT) intervention developed in Australia, is effective for treating major depressive disorder (MDD). The current study aimed to expand this work by adapting the protocol for an American population and testing the Sadness Program with an attention control group.
• Smith, R., Alkozei, A., & Killgore, W. D. (2017). Conflict-related dorsomedial frontal cortex activation during healthy food decisions is associated with increased cravings for high-fat foods. Brain imaging and behavior.
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  Previous studies suggest obesity is associated with altered function within the insula and dorsomedial frontal cortex (including dorsal anterior cingulate cortex; DMFC/dACC), reflecting abnormal reward processing and reduced sensitivity to feelings of satiety. Given the proposed roles of DMFC/dACC in monitoring response conflict and reward-based decision making, the present study examined DMFC/dACC activation, and functional connectivity between the DMFC/dACC and the anterior insula (AI), during food-related decision-making. Twenty participants recruited from the general population (10 Female) performed a decision task while undergoing functional magnetic resonance imaging. They were instructed to "choose the healthier option" when simultaneously shown pairs of images of different foods. Significant DMFC/dACC activation was observed during food-related decision-making, and activation levels also positively correlated with self-reported cravings for high-fat foods (r = 0.57, p = 0.009) and self-reported desire to eat the high-fat foods depicted in the images (r = 0.48, p = 0.032). Negative functional connectivity estimates between the right AI and DMFC/dACC were also associated with self-reported control over eating (r = -0.50, p = 0.025). These results suggest that (1) more intense cravings for unhealthy foods are associated with greater response conflict when deciding between healthy and unhealthy food options, and (2) lack of eating-related control may involve a reduced influence of insula-mediated bodily signals on decision-making. This task may offer a neuroimaging-based probe for identifying individuals vulnerable to eating-related disorders and should be replicated in clinical populations.
• Smith, R., Alkozei, A., & Killgore, W. D. (2017). Contributions of self-report and performance-based individual differences measures of social cognitive ability to large-scale neural network functioning. Brain imaging and behavior, 11(3), 685-697.
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  Adaptive social behavior appears to require flexible interaction between multiple large-scale brain networks, including the executive control network (ECN), the default mode network (DMN), and the salience network (SN), as well as interactions with the perceptual processing systems these networks function to modulate. Highly connected cortical "hub" regions are also thought to facilitate interactions between these networks, including the dorsolateral prefrontal cortex (DLPFC), dorsomedial prefrontal cortex (DMPFC), anterior cingulate cortex (ACC), and anterior insula (AI). However, less is presently known about the relationship between these network functions and individual differences in social-cognitive abilities. In the present study, 23 healthy adults (12 female) underwent functional magnetic resonance imaging (fMRI) while performing a visually based social judgment task (requiring the evaluation of social dominance in faces). Participants also completed both self-report and performance-based measures of emotional intelligence (EI), as well as measures of personality and facial perception ability. During scanning, social judgment, relative to a control condition involving simple perceptual judgment of facial features in the same stimuli, activated hub regions associated with each of the networks mentioned above (observed clusters included: bilateral DLPFC, DMPFC/ACC, AI, and ventral visual cortex). Interestingly, self-reported and performance-based measures of social-cognitive ability showed opposing associations with these patterns of activation. Specifically, lower self-reported EI and lower openness in personality both independently predicted greater activation within hub regions of the SN, DMN, and ECN (i.e., the DLPFC, DMPFC/ACC, and AI clusters); in contrast, in the same analyses greater scores on performance-based EI measures and on facial perception tasks independently predicted greater activation within hub regions of the SN and ECN (the DLPFC and AI clusters), and also in the ventral visual cortex. These findings suggest that lower confidence in one's own social-cognitive abilities may promote the allocation of greater cognitive resources to, and improve the performance of, social-cognitive functions.
• Smith, R., Alkozei, A., Bao, J., Smith, C., Lane, R. D., & Killgore, W. D. (2017). Resting state functional connectivity correlates of emotional awareness. NeuroImage, 159, 99-106.
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  Multiple neuroimaging studies have now linked emotional awareness (EA), as measured by the Levels of Emotional Awareness Scale (LEAS), with activation in regions of neural networks associated with both conceptualization (i.e., default mode network [DMN] regions) and interoception (i.e., salience network [SN] regions) - consistent with the definition of EA as one's ability to appropriately recognize, conceptualize, and articulate the emotions of self and other in fine-grained, differentiated ways. However, no study has yet tested the hypothesis that greater LEAS scores are associated with greater resting state functional connectivity (FC) within these networks. Twenty-six adults (13 female) underwent resting state functional magnetic resonance imaging, and also completed the LEAS. Using pre-defined functional ROIs from the DMN and SN, we observed that LEAS scores were significantly positively correlated with FC between several regions of both of these networks, even when controlling for differences in general intelligence (IQ). These results suggest that higher EA may be associated with more efficient information exchange between brain regions involved in both interoception- and conceptualization-based processing, which could plausibly contribute to more differentiated bodily feelings and more fine-grained conceptualization of those feelings.
• Smith, R., Killgore, W. D., & Lane, R. D. (2017). The Structure of Emotional Experience and Its Relation to Trait Emotional Awareness: A Theoretical Review. Emotion (Washington, D.C.).
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  Emotional experience (EE) and trait emotional awareness (tEA) have recently become topics of considerable experimental/theoretical interest within the cognitive and neural sciences. However, to date there has been limited empirical focus on how individual differences in the factors contributing to EE (a state-based construct) might account for differences in tEA. To promote clear, well-guided empirical research in this area, in this article we first offer a concise review of the primary factors contributing to EE. We then provide a theoretical investigation into how individual differences in these factors (i.e., differences in affective response generation, affective response representation, and conscious access) could mechanistically account for differences in tEA; we also discuss plausible origins of these individual differences in light of current empirical findings. Finally, we outline possible experiments that would support (or fail to support) the role of each factor in explaining differences in tEA-and how this added knowledge could shed light on the known link between low tEA and multiple emotion-related mental and systemic medical disorders. (PsycINFO Database Record
• Smith, R., Lane, R. D., Alkozei, A., Bao, J., Smith, C., Sanova, A., Nettles, M., & Killgore, W. D. (2017). Maintaining the feelings of others in working memory is associated with activation of the left anterior insula and left frontal-parietal control network. Social cognitive and affective neuroscience, 12(5), 848-860.
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  The maintenance of social/emotional information in working memory (SWM/EWM) has recently been the topic of multiple neuroimaging studies. However, some studies find that SWM/EWM involves a medial frontal-parietal network while others instead find lateral frontal-parietal activations similar to studies of verbal and visuospatial WM. In this study, we asked 26 healthy volunteers to complete an EWM task designed to examine whether different cognitive strategies- maintaining emotional images, words, or feelings- might account for these discrepant results. We also examined whether differences in EWM performance were related to general intelligence (IQ), emotional intelligence (EI), and emotional awareness (EA). We found that maintaining emotional feelings, even when accounting for neural activation attributable to maintaining emotional images/words, still activated a left lateral frontal-parietal network (including the anterior insula and posterior dorsomedial frontal cortex). We also found that individual differences in the ability to maintain feelings were positively associated with IQ and EA, but not with EI. These results suggest that maintaining the feelings of others (at least when perceived exteroceptively) involves similar frontal-parietal control networks to exteroceptive WM, and that it is similarly linked to IQ, but that it also may be an important component of EA.
• Alkozei, A., Schwab, Z. J., & Killgore, W. D. (2016). The role of emotional intelligence during an emotionally difficult decision-making task. Journal of Nonverbal Behavior, 40(1), 39--54.
• Alkozei, A., Smith, R., & Killgore, W. D. (2016). Exposure to blue wavelength light modulates anterior cingulate cortex activation in response to ‘uncertain’versus ‘certain’anticipation of positive stimuli. Neuroscience letters, 616, 5--10.
• Alkozei, A., Smith, R., Pisner, D. A., Vanuk, J. R., Berryhill, S. M., Fridman, A., Shane, B. R., Knight, S. A., & Killgore, W. D. (2016). Exposure to Blue Light Increases Subsequent Functional Activation of the Prefrontal Cortex During Performance of a Working Memory Task. Sleep, 39(9), 1671-80.
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  Prolonged exposure to blue wavelength light has been shown to have an alerting effect, and enhances performance on cognitive tasks. A small number of studies have also shown that relatively short exposure to blue light leads to changes in functional brain responses during the period of exposure. The extent to which blue light continues to affect brain functioning during a cognitively challenging task after cessation of longer periods of exposure (i.e., roughly 30 minutes or longer), however, has not been fully investigated.
• Alkozei, A., Smith, R., Pisner, D., Vanuk, J., Markowski, S., Fridman, A., Shane, B., Knight, S., & Killgore, W. (2016). Exposure to Blue Light Increases Subsequent Functional Activation of the Prefrontal Cortex During Performance of a Working Memory Task.. Sleep.
• Freed, M. C., Novak, L. A., Killgore, W. D., Rauch, S. A., Koehlmoos, T. P., Ginsberg, J. P., Krupnick, J. L., Rizzo, A. S., Andrews, A., & Engel, C. C. (2016). IRB and Research Regulatory Delays Within the Military Health System: Do They Really Matter? And If So, Why and for Whom?. The American journal of bioethics : AJOB, 16(8), 30-7.
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  Institutional review board (IRB) delays may hinder the successful completion of federally funded research in the U.S. military. When this happens, time-sensitive, mission-relevant questions go unanswered. Research participants face unnecessary burdens and risks if delays squeeze recruitment timelines, resulting in inadequate sample sizes for definitive analyses. More broadly, military members are exposed to untested or undertested interventions, implemented by well-intentioned leaders who bypass the research process altogether. To illustrate, we offer two case examples. We posit that IRB delays often appear in the service of managing institutional risk, rather than protecting research participants. Regulators may see more risk associated with moving quickly than risk related to delay, choosing to err on the side of bureaucracy. The authors of this article, all of whom are military-funded researchers, government stakeholders, and/or human subject protection experts, offer feasible recommendations to improve the IRB system and, ultimately, research within military, veteran, and civilian populations.
• Kelly, M. K., Killgore, W., & Haynes, P. L. (2016). Understanding Recent Insights in Sleep and Posttraumatic Stress Disorder from a Research Domain Criteria (RDoc) Framework. Current Sleep Medicine Reports, 2(4), 223-232.
• Kelly, M. R., Killgore, W. D., & Haynes, P. L. (2016). Understanding Recent Insights in Sleep and Posttraumatic Stress Disorder from a Research Domain Criteria (RDoC) Framework. Current Sleep Medicine Reports, 2(4), 223--232.
• Killgore, W. (2016). Lighting the Way to Better Sleep and Health. Journal of Sleep Disorders: Treatment and Care, 2016.
• Killgore, W. D., Singh, P., Kipman, M., Pisner, D., Fridman, A., & Weber, M. (2016). Gray matter volume and executive functioning correlate with time since injury following mild traumatic brain injury. Neuroscience letters, 612, 238--244.
• Killgore, W. D., Sonis, L. A., Rosso, I. M., & Rauch, S. L. (2016). Emotional Intelligence Partially Mediates the Association between Anxiety Sensitivity and Anxiety Symptoms. Psychological reports, 118(1), 23-40.
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  Anxiety Sensitivity (AS), the propensity to fear the somatic, mental, and social consequences of anxiety, is associated with an elevated risk of developing anxiety disorders. It was hypothesized that Emotional Intelligence (EI) might serve as a mediating variable between AS and anxiety symptom expression. Sixty-one healthy adults (30 men, 31 women; M age = 30.4 yr., SD = 8.0), recruited through posted advertisements, completed the Anxiety Sensitivity Index (ASI) and the ANX subscale of the Personality Assessment Inventory (PAI), as well as three assessments of EI, including two indices of the Ability model of EI (MSCEIT; SREIS), and one index of the Trait model of EI (i.e., Bar-On EQ-i). Partial mediation between AS and ANX was found for the EQ-i but not for the MSCEIT or SREIS, as determined by the bootstrap method of mediation analysis. The association between AS and anxiety symptoms was partly explained through its effects on the intervening variable of Trait EI, and points to the possibility that interventions improving Trait EI may be useful in reducing the expression of anxiety symptoms in people with high AS.
• Olson, E. A., Rosso, I. M., Demers, L. A., Divatia, S., & Killgore, W. D. (2016). Sex Differences in Psychological Factors Associated with Social Discounting. Journal of Behavioral Decision Making, 29(1), 60--66.
• Olson, E. A., Weber, M., Rauch, S. L., & Killgore, W. D. (2016). Daytime Sleepiness Is Associated With Reduced Integration of Temporally Distant Outcomes on the Iowa Gambling Task. Behavioral sleep medicine, 14(2), 200-11.
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  Sleep deprivation is associated with performance decrements on some measures of executive functioning. For instance, sleep deprivation results in altered decision making on the Iowa Gambling Task. However, it is unclear which component processes of the task may be driving the effect. In this study, Iowa Gambling task performance was decomposed using the Expectancy-Valence model. Recent sleep debt and greater daytime sleepiness were associated with higher scores on the updating parameter, which reflects the extent to which recent experiences are emphasized over remote ones. Findings suggest that the effects of insufficient sleep on IGT performance are due to shortening of the time horizon over which decisions are integrated. These findings may have clinical implications in that individuals with sleep problems may not integrate more temporally distant information when making decisions.
• Pisner, D. A., Smith, R., Alkozei, A., Klimova, A., & Killgore, W. D. (2016). Highways of the emotional intellect: white matter microstructural correlates of an ability-based measure of emotional intelligence. Social neuroscience, 1--15.
• Rosso, I. M., Killgore, W. D., Olson, E. A., Webb, C. A., Fukunaga, R., Auerbach, R. P., Gogel, H., Buchholz, J. L., & Rauch, S. L. (2016). Internet-based cognitive behavior therapy for major depressive disorder: A randomized controlled trial. Depression and Anxiety.
• Singh, P., & Killgore, W. D. (2016). Time dependent differences in gray matter volume post mild traumatic brain injury. Neural regeneration research, 11(6), 920-1.
• Smith, R., Alkozei, A., & Killgore, W. D. (2016). Contributions of self-report and performance-based individual differences measures of social cognitive ability to large-scale neural network functioning. Brain imaging and behavior, 1--13.
• Smith, R., Alkozei, A., Lane, R. D., & Killgore, W. D. (2016). Unwanted reminders: The effects of emotional memory suppression on subsequent neuro-cognitive processing. Consciousness and cognition, 44, 103-113.
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  The neural basis of voluntarily suppressing conscious access to one's own memories (retrieval suppression [RS]) has recently received considerable attention. However, to date there has been limited research examining the effects of RS on subsequent processing of associated retrieval cues. In this study 47 healthy participants completed a Think/No Think task for memories of emotionally unpleasant visual scenes. While undergoing functional magnetic resonance imaging (fMRI), participants were then presented with cues associated with both suppressed ("no-think-cues") and non-suppressed ("think-cues") memories, and then asked to perform simple arithmetic problems. We observed that, compared to think-cues, no-think-cues were associated with greater left mid/anterior insula activation and with greater insula-anterior cingulate functional connectivity; left insula activation also predicted worse arithmetic performance. These results suggest that cues associated with suppressed negative memories may lead to greater activation of the brain's "salience" network, and reduced available cognitive resources for completion of an ongoing goal-directed task.
• Alkozei, A., & Killgore, W. D. (2015). Emotional intelligence is associated with reduced insula responses to masked angry faces. NeuroReport, 26(10), 567--571.
• Brennan, B. P., Tkachenko, O., Schwab, Z. J., Juelich, R. J., Ryan, E. M., Athey, A. J., Pope, H. G., Jenike, M. A., Baker, J. T., Killgore, W. D., & others, . (2015). An Examination of Rostral Anterior Cingulate Cortex Function and Neurochemistry in Obsessive--Compulsive Disorder. Neuropsychopharmacology, 40(8), 1866--1876.
• Cui, J., Tkachenko, O., Gogel, H., Kipman, M., Preer, L. A., Weber, M., Divatia, S. C., Demers, L. A., Olson, E. A., Buchholz, J. L., & others, . (2015). Microstructure of frontoparietal connections predicts individual resistance to sleep deprivation. NeuroImage, 106, 123--133.
• Killgore, W. D., Olson, E. A., Rosso, I. M., Demers, L. A., & Divatia, S. (2015). Sex Differences in Psychological Factors Associated with Social Discounting: Social Discounting and Sex Differences. Journal of Behavioral Decision Making, 29(1), 60-66. doi:10.1002/bdm.1876
• Killgore, W. D., Vanuk, J. R., Knight, S. A., Markowski, S. M., Pisner, D., Shane, B., Fridman, A., & Alkozei, A. (2015). Daytime sleepiness is associated with altered resting thalamocortical connectivity. Neuroreport, 26(13), 779--784.
• Mundy, E. A., Weber, M., Rauch, S. L., Killgore, W. D., Simon, N. M., Pollack, M. H., & Rosso, I. M. (2015). Adult anxiety disorders in relation to trait anxiety and perceived stress in childhood. Psychological reports, 117(2), 473--489.
• Weber, M., Simon, N. M., Rosso, I. M., Rauch, S. L., Pollack, M. H., Mundy, E. A., & Killgore, W. D. (2015). ADULT ANXIETY DISORDERS IN RELATION TO TRAIT ANXIETY AND PERCEIVED STRESS IN CHILDHOOD.. Psychological reports, 117(2), 473-89. doi:10.2466/02.10.pr0.117c17z6
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  It is well established that objective early life stressors increase risk for anxiety disorders and that environmental stressors interact with dispositional factors such as trait anxiety. There is less information on how subjective perception of stress during childhood relates to later clinical anxiety. This study tested whether childhood perceived stress and trait anxiety were independently and interactively associated with adult anxiety disorders. Forty-seven adults diagnosed with anxiety disorders (M age = 34 yr., SD = 11) and 29 healthy participants (M = 33 yr., SD = 13) completed the adult Perceived Stress Scale, the State-Trait Anxiety Inventory, and the Global Perceived Early Life Events Scale as a measure of perceived stress during childhood. In a logistic regression model, high childhood perceived stress (β = 0.64) and trait anxiety (β = 0.11) were associated with significantly greater odds of adult anxiety disorder. The association between childhood perceived stress and adult anxiety remained significant when controlling for adult perceived stress. These findings suggest that children's perception of stress in their daily lives may be an important target of intervention to prevent the progression of stress into clinically significant anxiety.
• Cohen-Gilbert, J., Killgore, W., White, C., Schwab, Z., Crowley, D., Covell, M., Sneider, J., & Silveri, M. (2014). Differential influence of safe versus threatening facial expressions on decision-making during an inhibitory control task in adolescence and adulthood. Developmental science, 17(2), 212--223.
• Cui, J., Olson, E. A., Weber, M., Schwab, Z. J., Rosso, I. M., Rauch, S. L., & Killgore, W. D. (2014). Trait emotional suppression is associated with increased activation of the rostral anterior cingulate cortex in response to masked angry faces. NeuroReport, 25(10), 771--776.
• Dillon, D. G., Rosso, I. M., Pechtel, P., Killgore, W. D., Rauch, S. L., & Pizzagalli, D. A. (2014). Peril and pleasure: an rdoc-inspired examination of threat responses and reward processing in anxiety and depression. Depression and anxiety, 31(3), 233--249.
• Dillon, D. G., Rosso, I. M., Pechtel, P., Killgore, W., Rauch, S. L., & Pizzagalli, D. A. (2014). PERIL AND PLEASURE: AN RDOC-INSPIRED EXAMINATION OF THREAT RESPONSES AND REWARD PROCESSING IN ANXIETY AND DEPRESSION. DEPRESSION AND ANXIETY, 31(3), 233-249.
• Killgore, W. D., & Gogel, H. (2014). The Design Organization Test: Further demonstration of reliability and validity as a brief measure of visuospatial ability. Applied Neuropsychology: Adult, 21(4), 297--309.
• Killgore, W. D., Britton, J. C., Schwab, Z. J., Price, L. M., Weiner, M. R., Gold, A. L., Rosso, I. M., Simon, N. M., Pollack, M. H., & Rauch, S. L. (2014). CORTICO-LIMBIC RESPONSES TO MASKED AFFECTIVE FACES ACROSS PTSD, PANIC DISORDER, AND SPECIFIC PHOBIA. Depression and anxiety, 31(2), 150--159.
• Killgore, W. D., Britton, J. C., Schwab, Z. J., Price, L. M., Weiner, M. R., Gold, A. L., Rosso, I. M., Simon, N. M., Pollack, M. H., & Rauch, S. L. (2014). Cortico-limbic responses to masked affective faces across ptsd, panic disorder, and specific phobia. Depression and anxiety, 31(2), 150-9.
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  Exaggerated amygdala and reduced ventromedial prefrontal cortex (vmPFC) responsiveness during emotional processing have been reported in studies examining individual anxiety disorders. Studies are needed, however, which directly compare activation of amygdalo-cortical circuitry across multiple anxiety disorders within the same study. Here we compared cortico-limbic neurocircuitry across three different anxiety disorders using a well-validated emotional probe task.
• Killgore, W. D., Kamimori, G. H., & Balkin, T. J. (2014). Caffeine improves the efficiency of planning and sequencing abilities during sleep deprivation. Journal of clinical psychopharmacology, 34(5), 660--662.
• Killgore, W., Britton, J. C., Schwab, Z. J., Price, L. M., Weiner, M. R., Gold, A. L., Rosso, I. M., Simon, N. M., Pollack, M. H., & Rauch, S. L. (2014). CORTICO-LIMBIC RESPONSES TO MASKED AFFECTIVE FACES ACROSS PTSD, PANIC DISORDER, AND SPECIFIC PHOBIA. DEPRESSION AND ANXIETY, 31(2), 150-159.
• Preer, L., Tkachenko, O., Gogel, H., Bark, J., & Killgore, W. (2014). Personality Traits Associated with Sleep Initiation Problems. J Sleep Disor: Treat Care 3: 1. of, 5, 18--45.
• Rosso, I. M., Olson, E. A., Britton, J. C., Stewart, S. E., Papadimitriou, G., Killgore, W. D., Makris, N., Wilhelm, S., Jenike, M. A., & Rauch, S. L. (2014). Brain white matter integrity and association with age at onset in pediatric obsessive-compulsive disorder. Biology of mood \& anxiety disorders, 4(1), 1.
• Tkachenko, O., Olson, E. A., Weber, M., Preer, L. A., Gogel, H., & Killgore, W. D. (2014). Sleep difficulties are associated with increased symptoms of psychopathology. Experimental brain research, 232(5), 1567--1574.
• Webb, C. A., DelDonno, S., & Killgore, W. D. (2014). The role of cognitive versus emotional intelligence in Iowa Gambling Task performance: What's emotion got to do with it?. Intelligence, 44, 112--119.
• Webb, C. A., Weber, M., Mundy, E. A., & Killgore, W. (2014). Reduced gray matter volume in the anterior cingulate, orbitofrontal cortex and thalamus as a function of mild depressive symptoms: a voxel-based morphometric analysis. PSYCHOLOGICAL MEDICINE, 44(13), 2833-2843.
• Webb, C. A., Weber, M., Mundy, E. A., & Killgore, W. D. (2014). Reduced gray matter volume in the anterior cingulate, orbitofrontal cortex and thalamus as a function of mild depressive symptoms: a voxel-based morphometric analysis. Psychological medicine, 44(13), 2833--2843.
• Killgore, W. (2013). Self-reported sleep correlates with prefrontal-amygdala functional connectivity and emotional functioning. Sleep, 36(11), 1597--608.
• Killgore, W. D., Kipman, M., Schwab, Z. J., Tkachenko, O., Preer, L., Gogel, H., Bark, J. S., Mundy, E. A., Olson, E. A., & Weber, M. (2013). Physical exercise and brain responses to images of high-calorie food. Neuroreport, 24(17), 962--967.
• Killgore, W. D., Olson, E. A., & Weber, M. (2013). Physical exercise habits correlate with gray matter volume of the hippocampus in healthy adult humans. Scientific reports, 3.
• Killgore, W. D., Schwab, Z. J., Kipman, M., DelDonno, S. R., & Weber, M. (2013). Insomnia-related complaints correlate with functional connectivity between sensory--motor regions. Neuroreport, 24(5), 233--240.
• Killgore, W. D., Schwab, Z. J., Tkachenko, O., Webb, C. A., DelDonno, S. R., Kipman, M., Rauch, S. L., & Weber, M. (2013). Emotional intelligence correlates with functional responses to dynamic changes in facial trustworthiness. Social neuroscience, 8(4), 334-46.
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  Emotional intelligence (EI) refers to a constellation of traits, competencies, or abilities that allow individuals to understand emotional information and successfully navigate and solve social/emotional problems. While little is known about the neurobiological substrates that underlie EI, some evidence suggests that these capacities may involve a core neurocircuitry involved in emotional decision-making that includes the ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC), insula, and amygdala. In a sample of 39 healthy volunteers (22 men; 17 women), scores on the Bar-On EQ-i (a trait/mixed model of EI) and Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT; an ability model of EI) were correlated with functional magnetic resonance imaging responses during brief presentations of moving facial expressions that changed in the level of perceived trustworthiness. Core emotion neurocircuitry was responsive to dynamic changes in facial features, regardless of whether they reflected increases or decreases in apparent trustworthiness. In response to facial movements indicating decreasing trustworthiness, MSCEIT correlated positively with functional responses of the vmPFC and rostral ACC, whereas the EQ-i was unrelated to regional activation. Systematic differences in EI ability appear to be significantly related to the responsiveness of the vmPFC and rostral ACC to facial movements suggesting potential trustworthiness.
• Killgore, W. D., Schwab, Z. J., Weber, M., Kipman, M., DelDonno, S. R., Weiner, M. R., & Rauch, S. L. (2013). Daytime sleepiness affects prefrontal regulation of food intake. Neuroimage, 71, 216--223.
• Killgore, W., Olson, E. A., & Weber, M. (2013). Physical Exercise Habits Correlate with Gray Matter Volume of the Hippocampus in Healthy Adult Humans. SCIENTIFIC REPORTS, 3.
• Killgore, W., Weber, M., Schwab, Z., Kipman, M., DelDonno, S., Webb, C., & Rauch, S. (2013). Cortico-limbic responsiveness to high-calorie food images predicts weight status among women. International Journal of Obesity, 37(11), 1435--1442.
• Thomas, J. J., Hartmann, A. S., & Killgore, W. D. (2013). Non-fat-phobic eating disorders: Why we need to investigate implicit associations and neural correlates. International Journal of Eating Disorders, 46(5), 416--419.
• Webb, C. A., Schwab, Z. J., Weber, M., DelDonno, S., Kipman, M., Weiner, M. R., & Killgore, W. (2013). Convergent and divergent validity of integrative versus mixed model measures of emotional intelligence. INTELLIGENCE, 41(3), 149-156.
• Webb, C. A., Schwab, Z. J., Weber, M., DelDonno, S., Kipman, M., Weiner, M. R., & Killgore, W. D. (2013). Convergent and divergent validity of integrative versus mixed model measures of emotional intelligence. Intelligence, 41(3), 149--156.
• Weber, M., & Killgore, W. D. (2013). What are the emerging therapeutic uses of bright light therapy for neurological disorders?. Future Neurology, 8(5), 495--497.
• Weber, M., Killgore, W. D., Rosso, I. M., Britton, J. C., Schwab, Z. J., Weiner, M. R., Simon, N. M., Pollack, M. H., & Rauch, S. L. (2013). Voxel-based morphometric gray matter correlates of posttraumatic stress disorder. Journal of anxiety disorders, 27(4), 413--419.
• Weber, M., Webb, C. A., & Killgore, W. D. (2013). A brief and selective review of treatment approaches for sleep disturbance following traumatic brain injury. Journal of Sleep Disorders \& Therapy, 2013.
• Weber, M., Webb, C. A., Deldonno, S. R., Kipman, M., Schwab, Z. J., Weiner, M. R., & Killgore, W. D. (2013). Habitual ‘sleep credit’is associated with greater grey matter volume of the medial prefrontal cortex, higher emotional intelligence and better mental health. Journal of sleep research, 22(5), 527--534.
• Gruber, S. A., Dahlgren, M. K., Sagar, K. A., Goenenc, A., & Killgore, W. (2012). Age of onset of marijuana use impacts inhibitory processing. NEUROSCIENCE LETTERS, 511(2), 89-94.
• Gruber, S. A., Dahlgren, M. K., Sagar, K. A., Gönenc, A., & Killgore, W. D. (2012). Age of onset of marijuana use impacts inhibitory processing. Neuroscience letters, 511(2), 89-94.
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  Difficulties in the ability to successfully inhibit impulsive behaviors have been reported in marijuana (MJ) smokers, yet few studies have made direct comparisons between early (prior to age 16) and late (age 16 or later) onset MJ smokers, specifically during behavioral inhibition tasks. The current study utilized the Multi-Source Interference Task (MSIT) during functional magnetic resonance imaging (fMRI) in chronic, heavy MJ smokers and healthy non-MJ smoking controls which revealed a more focal pattern of anterior cingulate activity in controls relative to smokers. Early onset smokers had more focal activation but tended to make more errors of commission relative to late onset smokers, suggesting a possible neural adaptation despite difficulty with behavioral inhibition. Further investigation is warranted, as early exposure to MJ may result in reorganization of critical brain regions.
• Killgore, W. (2012). Sleepless Nights and Bulging Waistlines. J Sleep Disor: Treat Care 1: 1. doi: 10.4172/. 1000e101.
• Killgore, W. D. (2012). NOctuRNal POlySOmNOgRaPhIc cORRelateS Of DaytIme SleePINeSS1, 2. Psychological reports, 110(1), 63--72.
• Killgore, W. D., & Schwab, Z. J. (2012). Sex differences in the association between physical exercise and IQ. Perceptual and motor skills, 115(2), 605-17.
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  Previous research suggests that physical exercise may have beneficial effects on cognitive performance in children and the elderly, but little research has yet examined these associations in healthy adults. It was hypothesized that self-reported frequency and duration of physical exercise would correlate positively with measured intelligence on the Wechsler Abbreviated Scale of Intelligence in healthy young to middle aged adults (25 men, 28 women). Although there was a modest positive association between physical exercise and intelligence (IQ) for the group as a whole, when examined separately by sex, greater physical activity was associated with higher intelligence scores for women, whereas exercise level was essentially unrelated to intelligence among men. These associations remained consistent even after controlling for demographic and socioeconomic factors. The association between exercise and IQ appears to be moderated by sex in healthy adults, possibly through its effects on glucoregulation, insulin sensitivity, or other factors that differ between men and women.
• Killgore, W. D., Capaldi, V. F., & Guerrero, M. L. (2012). Nocturnal polysomnographic correlates of daytime sleepiness. Psychological reports, 110(1), 63-72.
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  The relations of nighttime polysomnographic sleep variables with daytime sleepiness scores on the Epworth Sleepiness Scale were assessed in a retrospective chart review of 38 patients referred to a sleep clinic. Of the variables assessed, only slow wave sleep was statistically significantly correlated with daytime sleepiness, regardless of whether the analysis was based on absolute minutes of slow wave sleep or percentage of total sleep time spent in slow wave sleep. Stepwise linear regression suggested that other polysomnographic variables did not provide additional predictive value beyond the two indices of slow wave sleep. Apparently, reduced quantity of slow wave sleep was weakly but significantly related to increased daytime sleepiness among these sleep-clinic patients.
• Killgore, W. D., Grugle, N. L., & Balkin, T. J. (2012). Gambling when sleep deprived: don't bet on stimulants. Chronobiology international, 29(1), 43-54.
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  Recent evidence suggests that sleep deprivation leads to suboptimal decision-making on the Iowa Gambling Task (IGT), a pattern that appears to be unaffected by moderate doses of caffeine. It is not known whether impaired decision-making could be reversed by higher doses of caffeine or by other stimulant countermeasures, such as dextroamphetamine or modafinil. Fifty-four diurnally active healthy subjects completed alternate versions of the IGT at rested baseline, at 23 and 46 h awake, and following a night of recovery sleep. After 44 h awake, participants received a double-blind dose of caffeine (600 mg), dextroamphetamine (20 mg), modafinil (400 mg), or placebo. At baseline, participants showed a normal pattern of advantageous performance, whereas both sleep-deprived sessions were associated with suboptimal decision-making on the IGT. Following stimulant administration on the second night of sleep deprivation, groups receiving caffeine, dextroamphetamine, or modafinil showed significant reduction in subjective sleepiness and improvement in psychomotor vigilance, but decision-making on the IGT remained impaired for all stimulants and did not differ from placebo. Decision-making returned to normal following recovery sleep. These findings are consistent with prior research showing that sleep deprivation leads to suboptimal decision-making on some types of tasks, particularly those that rely heavily on emotion processing regions of the brain, such as the ventromedial prefrontal cortex. Moreover, the deficits in decision-making were not reversed by commonly used stimulant countermeasures, despite restoration of psychomotor vigilance and alertness. These three stimulants may restore some, but not all, aspects of cognitive functioning during sleep deprivation.
• Killgore, W. D., Schwab, Z. J., & Weiner, M. R. (2012). Self-reported nocturnal sleep duration is associated with next-day resting state functional connectivity. Neuroreport, 23(13), 741-5.
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  Sleep deprivation affects cerebral metabolism and reduces the functional connectivity among various regions of the brain, potentially explaining some of the associated mood and emotional changes often observed. Prior neuroimaging studies have only examined the effects of sleep deprivation or partial sleep restriction on functional connectivity, but none have studied how such connectivity is associated with normal variations in self-reported sleep duration the night before the scan. We examined the relationship between sleep duration and resting state functional connectivity among healthy volunteers who slept at home according to their own schedules. Thirty-nine healthy individuals aged 18-45 (21 females) completed a questionnaire asking about their recent sleep habits and entries in their sleep diary for the previous night, followed by resting state functional MRI at 3 T. Participants reported sleeping between 5.0 and 8.5 h the night before the scan (M=7.0, SD=0.9). Seed regions were placed in the medial prefrontal cortex and posterior cingulate cortex nodes of the default mode network, regions previously implicated in sleep deprivation. Longer self-reported sleep duration was associated with significantly enhanced functional connectivity between the medial prefrontal cortex and posterior cingulate, as well as greater anticorrelations with parietal, occipital, and lateral prefrontal regions. Findings suggest that even normal variations in sleep duration measured by self-report are related to the strength of functional connectivity within select nodes of the default mode network and its anticorrelated network.
• Killgore, W. D., Schwab, Z. J., Kipman, M., DelDonno, S. R., & Weber, M. (2012). Voxel-based morphometric gray matter correlates of daytime sleepiness. Neuroscience letters, 518(1), 10-3.
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  Sleep disorders such as narcolepsy, obstructive sleep apnea, and chronic insomnia have been associated with reduced gray matter volume of the ventromedial prefrontal cortex (VMPFC). Functional neuroimaging and behavioral data also implicate this region as important in sleep-related problems and the ability to resist the impairing effects of sleep loss on cognition. However, no study has linked gray matter volume within this region to normal self-reported levels of daytime sleepiness. We therefore hypothesized that reduced gray matter volume within the VMPFC would be related to greater self-reported levels of general daytime sleepiness, as assessed by the Epworth Sleepiness Scale (ESS) in a sample of 36 healthy non-clinical participants. Using voxel-based morphometry, scores of the ESS were correlated with gray matter volume, after controlling for age, gender, and whole brain volume. Daytime sleepiness correlated negatively with gray matter volume in a cluster of voxels within the left gyrus rectus and medial orbitofrontal cortex. Findings converge with prior evidence to suggest that the VMPFC and medial orbitofrontal cortex may play a particularly important role in sleep-wake related phenomena including sleep disorders and trait-like individual differences in vulnerability to the impairing effects of sleep deprivation on neurobehavioral performance, and also in normal variations in self-reported daytime sleepiness.
• Killgore, W. D., Weber, M., Schwab, Z. J., Deldonno, S. R., Kipman, M., Weiner, M. R., & Rauch, S. L. (2012). Gray matter correlates of Trait and Ability models of emotional intelligence. Neuroreport, 23(9), 551-5.
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  Research suggests that emotional intelligence capacities may be related to the functional integrity of the corticolimbic regions including the ventromedial prefrontal cortex, insula, and amygdala. No study has yet examined regional brain volumes in relation to the two dominant models of emotional intelligence: the Ability model, which posits a set of specific demonstrable capabilities for solving emotional problems, and the Trait model, which proposes a set of stable emotional competencies that can be assessed through subjectively rated self-report scales. In 36 healthy participants, we correlated scores on the Mayer-Salovey-Caruso Emotional Intelligence Test (an Ability measure) and the Bar-On Emotional Quotient Inventory (a Trait measure) with regional brain volumes using voxel-based morphometry. Total Mayer-Salovey-Caruso Emotional Intelligence Test scores were positively correlated with the left insula grey matter volume. The Strategic emotional intelligence subscale correlated positively with the left ventromedial prefrontal cortex and insular volume. In contrast, for the Bar-On Emotional Quotient Inventory, Stress Management scores correlated positively with the bilateral ventromedial prefrontal cortex volume. Amygdala volumes were unrelated to emotional intelligence measures. Findings support the role of the ventromedial prefrontal cortex and insula as key nodes in the emotional intelligence circuitry.
• Killgore, W., Grugle, N. L., & Balkin, T. J. (2012). Gambling When Sleep Deprived: Don't Bet on Stimulants. CHRONOBIOLOGY INTERNATIONAL, 29(1), 43-54.
• Kipman, M., Weber, M., Schwab, Z. J., DelDonno, S. R., & Killgore, W. D. (2012). A funny thing happened on the way to the scanner: humor detection correlates with gray matter volume. Neuroreport, 23(18), 1059-64.
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  The detection and appreciation of humor is a complex cognitive process that remains poorly understood. Although functional neuroimaging studies have begun to map the brain systems involved in humor appreciation, there are virtually no data on the structural correlates between gray matter volume and this capacity. Using voxel-based morphometry, the present study examined the association between gray matter volume and the ability to detect and appreciate humor. Fifty-nine healthy adults aged 18-45 years (30 men) underwent structural MRI and completed the University of Pennsylvania Humor Appreciation Test (HAT). After controlling for age and sex, gray matter volume of the left inferior frontal gyrus, left temporal pole, and left insula correlated positively with the appreciation of visual and verbal humor on the HAT, whereas the gray matter volume of the right inferior frontal gyrus correlated only with verbal humor appreciation scores. There were no negative correlations between gray matter volume and HAT performance. These data support a neurobiological basis for humor appreciation, particularly involving left-hemispheric cortical systems, and further suggest that individual differences in humor appreciation may be related to differences in regional gray matter volume.
• Capaldi, V. F., Guerrero, M. L., & Killgore, W. D. (2011). Sleep disruptions among returning combat veterans from Iraq and Afghanistan. Military medicine, 176(8), 879-88.
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  Post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI) are common injuries among returning combat veterans from the wars in Iraq and Afghanistan. Although these combat injuries have been associated with increased sleep disruption, little is known about the nature and specificity of sleep problems within these common injury categories.
• Capaldi, V., Guerrero, M. L., & Killgore, W. (2011). Sleep Disruptors Among Returning Combat Veterans From Iraq and Afghanistan. MILITARY MEDICINE, 176(8), 879-888.
• Ferr{\'e}, S., Jensen, M. B., Kempf, K., Martin, S., Kolb, H., Temple, J. L., Nardi, A. E., O'Connor, P. J., Simola, N., Morelli, M., & others, . (2011). What Do You See as the Main Priorities, Opportunities, and Challenges in Caffeine Research in the Next Five Years?. Journal of Caffeine Research, 1(1), 5--12.
• Killgore, W. D., Britton, J. C., Price, L. M., Gold, A. L., Deckersbach, T., & Rauch, S. L. (2011). Neural correlates of anxiety sensitivity during masked presentation of affective faces. Depression and anxiety, 28(3), 243-9.
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  Anxiety Sensitivity (AS), the tendency to fear the thoughts, symptoms, and social consequences associated with the experience of anxiety, is associated with increased risk for developing anxiety disorders. Some evidence suggests that higher scores on the Anxiety Sensitivity Index (ASI), a measure of the AS construct, are associated with activation of the anterior insular cortex during overt emotion perception. Although the ASI provides subscale scores measuring Physical, Mental Incapacitation, and Social Concerns of AS, no study has examined the relationship between these factors and regional brain activation during affect processing. We hypothesized that insular responses to fear-related stimuli would be primarily related to the Physical Concerns subscale of the ASI, particularly for a sample of subjects with specific phobias.
• Killgore, W. D., Kamimori, G. H., & Balkin, T. J. (2011). Caffeine protects against increased risk-taking propensity during severe sleep deprivation. Journal of sleep research, 20(3), 395--403.
• Killgore, W. D., Kamimori, G. H., & Balkin, T. J. (2011). Caffeine protects against increased risk-taking propensity during severe sleep deprivation. Journal of sleep research, 20(3), 395-403.
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  Previous research suggests that sleep deprivation is associated with declines in metabolic activity within brain regions important for judgement and impulse control, yet previous studies have reported inconsistent findings regarding the effects of sleep loss and caffeine on risk-taking. In this study, 25 healthy adults (21 men, four women) completed the Balloon Analog Risk Task (BART) and Evaluation of Risks (EVAR) scale at regular intervals to examine behavioral and self-reported risk-taking propensity during 75 h of continuous sleep deprivation. Participants received either four double-blind administrations of 200 mg caffeine (n=12) or indistinguishable placebo (n=13) gum bi-hourly during each of the 3 nights of sleep deprivation. No significant effects of drug group or sleep deprivation were evident on the BART or EVAR when measured at 51 h of wakefulness. However, by 75 h, the placebo group showed a significant increase in risk-taking behavior on the cost-benefit ratio and total number of exploded balloons on the BART, whereas the caffeine group remained at baseline levels. On the EVAR, several factors of self-reported risk-taking propensity, including total risk, impulsivity and risk/thrill seeking, were reduced among subjects receiving caffeine across the 3 days of sleep deprivation, but remained at baseline levels for the placebo group. These results suggest that 3 nights of total sleep deprivation led to a significant increase in behavioral risk-taking but not self-reported perception of risk-propensity. Overnight caffeine prevented this increase in risky behavior.
• Britton, J. C., Rauch, S. L., Rosso, I. M., Killgore, W. D., Price, L. M., Ragan, J., Chosak, A., Hezel, D. M., Pine, D. S., Leibenluft, E., Pauls, D. L., Jenike, M. A., & Stewart, S. E. (2010). Cognitive inflexibility and frontal-cortical activation in pediatric obsessive-compulsive disorder. Journal of the American Academy of Child and Adolescent Psychiatry, 49(9), 944-53.
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  Deficits in cognitive flexibility and response inhibition have been linked to perturbations in cortico-striatal-thalamic circuitry in adult obsessive-compulsive disorder (OCD). Although similar cognitive deficits have been identified in pediatric OCD, few neuroimaging studies have been conducted to examine its neural correlates in the developing brain. In this study, we tested hypotheses regarding group differences in the behavioral and neural correlates of cognitive flexibility in a pediatric OCD and a healthy comparison (HC) sample.
• Britton, J. C., Rauch, S. L., Rosso, I. M., Killgore, W., Price, L. M., Ragan, J., Chosak, A., Hezel, D. M., Pine, D. S., Leibenluft, E., Pauls, D. L., Jenike, M. A., & Stewart, S. E. (2010). Cognitive Inflexibility and Frontal-Cortical Activation in Pediatric Obsessive-Compulsive Disorder. JOURNAL OF THE AMERICAN ACADEMY OF CHILD AND ADOLESCENT PSYCHIATRY, 49(9), 944-953.
• Britton, J. C., Stewart, S. E., Killgore, W. D., Rosso, I. M., Price, L. M., Gold, A. L., Pine, D. S., Wilhelm, S., Jenike, M. A., & Rauch, S. L. (2010). Amygdala activation in response to facial expressions in pediatric obsessive-compulsive disorder. Depression and anxiety, 27(7), 643-51.
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  Exaggerated amygdala activation to threatening faces has been detected in adults and children with anxiety disorders, compared to healthy comparison (HC) subjects. However, the profile of amygdala activation in response to facial expressions in obsessive-compulsive disorder (OCD) may be a distinguishing feature; a prior study found that compared with healthy adults, adults with OCD exhibited less amygdala activation to emotional and neutral faces, relative to fixation [Cannistraro et al. (2004). Biological Psychiatry 56:916-920].
• Killgore, W. (2010). Effects of sleep deprivation on cognition. HUMAN SLEEP AND COGNITION, PART I: BASIC RESEARCH, 185, 105-129.
• Killgore, W. (2010). Effects of sleep deprivation on cognition. Human Sleep and Cognition: Basic Research, 185, 105.
• Killgore, W. D. (2010). Asleep at the trigger: Warfighter judgment and decisionmaking during prolonged wakefulness. The 71F Advantage, 59.
• Killgore, W. D. (2010). Effects of sleep deprivation on cognition. Progress in brain research, 185, 105-29.
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  Sleep deprivation is commonplace in modern society, but its far-reaching effects on cognitive performance are only beginning to be understood from a scientific perspective. While there is broad consensus that insufficient sleep leads to a general slowing of response speed and increased variability in performance, particularly for simple measures of alertness, attention and vigilance, there is much less agreement about the effects of sleep deprivation on many higher level cognitive capacities, including perception, memory and executive functions. Central to this debate has been the question of whether sleep deprivation affects nearly all cognitive capacities in a global manner through degraded alertness and attention, or whether sleep loss specifically impairs some aspects of cognition more than others. Neuroimaging evidence has implicated the prefrontal cortex as a brain region that may be particularly susceptible to the effects of sleep loss, but perplexingly, executive function tasks that putatively measure prefrontal functioning have yielded inconsistent findings within the context of sleep deprivation. Whereas many convergent and rule-based reasoning, decision making and planning tasks are relatively unaffected by sleep loss, more creative, divergent and innovative aspects of cognition do appear to be degraded by lack of sleep. Emerging evidence suggests that some aspects of higher level cognitive capacities remain degraded by sleep deprivation despite restoration of alertness and vigilance with stimulant countermeasures, suggesting that sleep loss may affect specific cognitive systems above and beyond the effects produced by global cognitive declines or impaired attentional processes. Finally, the role of emotion as a critical facet of cognition has received increasing attention in recent years and mounting evidence suggests that sleep deprivation may particularly affect cognitive systems that rely on emotional data. Thus, the extent to which sleep deprivation affects a particular cognitive process may depend on several factors, including the magnitude of global decline in general alertness and attention, the degree to which the specific cognitive function depends on emotion-processing networks, and the extent to which that cognitive process can draw upon associated cortical regions for compensatory support.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2010). Cerebral Correlates of Amygdala Responses During Non-Conscious Perception of Facial Affect in Adolescent and Pre-Adolescent Children. Cognitive neuroscience, 1(1), 33-43.
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  During nonconscious perception of facial affect, healthy adults commonly activate a right-lateralized pathway comprising the superior colliculus, pulvinar, and amygdala. Whether this system is fully developed prior to adulthood is unknown. Twenty-three healthy adolescents underwent functional magnetic resonance imaging (fMRI) while viewing fearful, angry, and happy faces, backward masked by neutral faces. Left amygdala activation differed among the three affects, showing reductions to masked anger and increases to masked fear and happy faces. During masked fear, left amygdala activation correlated positively with extrastriate cortex and temporal poles and negatively with precuneus and middle cingulate gyrus. Responses of the left amygdala to masked anger correlated positively with right parahippocampal gyrus and negatively with dorsal anterior cingulate. Amygdala responses to masked happy faces were uncorrelated with other brain regions. Contrary to the right-lateralized pathway seen in adults, adolescents show evidence of a predominantly left-lateralized extrastriate pathway during masked presentations of facial affect.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2010). Sex differences in cerebral responses to images of high versus low-calorie food. Neuroreport, 21(5), 354-8.
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  Men and women differ in cerebral organization and prevalence rates of eating disorders. However, no studies have yet examined sex differences in cerebral responses to the caloric content of food images. Sixteen healthy adults (eight men; eight women) underwent functional magnetic resonance imaging while viewing images of high-calorie and low-calorie foods. Compared with men, women showed significantly greater activation to calorie-rich foods within dorsolateral, ventrolateral, and ventromedial prefrontal cortex, middle/posterior cingulate, and insula. Men failed to show greater activation in any cortical region compared with women, although amygdala responses were greater in men at a more liberal threshold. When viewing high-calorie food images, women seem more responsive than men within cortical regions involved in behavioral control and self-referential cognition.
• Killgore, W. D., Castro, C. A., & Hoge, C. W. (2010). Preliminary normative data for the Evaluation of Risks Scale-Bubble Sheet Version (EVAR-B) for large-scale surveys of returning combat veterans. Military medicine, 175(10), 725-31.
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  The Evaluation of Risks (EVAR) scale has been used to assess risk-taking propensity in military samples. This report provides preliminary reliability, validity, and normative data on a modified version of the instrument designed to facilitate data entry with optical scanners, the Evaluation of Risks-Bubble Sheet version (EVAR-B).
• Killgore, W. D., Grugle, N. L., Killgore, D. B., & Balkin, T. J. (2010). Sex differences in self-reported risk-taking propensity on the Evaluation of Risks scale. Psychological reports, 106(3), 693-700.
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  The Evaluation of Risks scale was recently developed as a self-report inventory for assessing risk-taking propensity, but further validation is necessary because most studies have predominantly included male subjects. Because males commonly exhibit greater risk-taking propensity than females, evidence of such a sex difference on the scale would further support its construct validity. 29 men and 25 women equated for age (range: 18 to 36 years) completed the scale. Internal consistency of the scale was generally modest, particularly among women. Men scored significantly higher than women on four of nine indices of risk-taking propensity, including Danger Seeking, Energy, Invincibility, and Total Risk-Propensity. Factors measuring thrill seeking and danger seeking correlated positively with a concurrent measure of sensation seeking. Although the higher scores exhibited by men are consistent with prior research on other measures of risk-taking, further research on this scale with samples including women is warranted.
• Killgore, W. D., Kelley, A., & Balkin, T. J. (2010). So you think you're bulletproof: Development and validation of the Invincibility Belief Index (IBI). Military medicine, 175(7), 499-508.
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  Risk-taking propensity can be influenced by sensation-seeking traits and self-perceived invincibility. We hypothesized that the latter factor may reflect a stable trait that endures across situations and may influence risk-taking behavior. We developed and validated a 20-item scale, the Invincibility Belief Index (IBI) to measure this construct. The IBI demonstrated good internal consistency and excellent test-retest reliability in the development sample (n = 100) and sustained similar levels of reliability in a cross-validation sample (n = 74). Principal components analysis yielded three orthogonal factors measuring self-perceived impunity (immunity from consequences), boldness/audacity (self-assuredness and competitiveness), and adroitness (mental agility and survival skill). In the prediction of risk taking, IBI scores contributed additional unique variance beyond sensation-seeking scores alone. IBI scores demonstrated convergent and discriminant validity with concurrently administered measures. These preliminary results support the reliability and validity of the IBI as a brief measure of self-perceived vulnerability-invincibility in the face of adversity.
• Killgore, W. D., Killgore, D. B., Grugle, N. L., & Balkin, T. J. (2010). Odor identification ability predicts executive function deficits following sleep deprivation. The International journal of neuroscience, 120(5), 328-34.
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  Odor identification ability is sensitive to prefrontal lobe dysfunction and preliminary evidence suggests that this capacity may decline with prolonged wakefulness. We hypothesized that declines in odor identification during a single night of sleep loss might, therefore, be predictive of prefrontal lobe executive function deficits following an additional night of sleep deprivation. Change scores between two administrations of the University of Pennsylvania Smell Identification Test (SIT) during 24 hr of sleep deprivation were used to predict performance on the Wisconsin Card Sorting Test (WCST) following 45 hr of wakefulness in 54 healthy adults. Declines in SIT performance predicted poorer performance on the WCST following an additional night of sleep loss. These findings suggest that individual differences in vulnerability to the effects of sleep loss on odor identification ability are predictive of deficits in executive functioning following additional wakefulness. Odor identification ability may provide an unobtrusive method for assessing vulnerability to sleep deprivation.
• Killgore, W. D., Ross, A. J., Kamiya, T., Kawada, Y., Renshaw, P. F., & Yurgelun-Todd, D. A. (2010). Citicoline affects appetite and cortico-limbic responses to images of high-calorie foods. The International journal of eating disorders, 43(1), 6-13.
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  Cytidine-5'-diphosphocholine (citicoline) has a variety of cognitive enhancing, neuroprotective, and neuroregenerative properties. In cocaine-addicted individuals, citicoline has been shown to increase brain dopamine levels and reduce cravings. The effects of this compound on appetite, food cravings, and brain responses to food are unknown.
• Killgore, W., & Yurgelun-Todd, D. A. (2010). Sex differences in cerebral responses to images of high versus low-calorie food. NEUROREPORT, 21(5), 354-358.
• Rosso, I. M., Makris, N., Britton, J. C., Price, L. M., Gold, A. L., Zai, D., Bruyere, J., Deckersbach, T., Killgore, W. D., & Rauch, S. L. (2010). Anxiety sensitivity correlates with two indices of right anterior insula structure in specific animal phobia. Depression and anxiety, 27(12), 1104-10.
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  Anxiety sensitivity (AS) is a dispositional trait involving fear of anxiety-related symptoms. Functional imaging research suggests that the activity of the anterior insular cortex, particularly the right insula, may both mediate AS and play a role in the pathophysiology of phobias. However, no imaging studies have examined whether AS relates to insula morphology. We examined whether AS was significantly correlated with right anterior insula volume and thickness among adults with specific animal phobia (SAP) and healthy comparison (HC) subjects.
• Rupp, T. L., Killgore, W. D., & Balkin, T. J. (2010). Socializing by Day May Affect Performance by Night: Vulnerability to Sleep Deprivation is Differentially Mediated by Social Exposure in Extraverts vs Introverts. Sleep, 33(11), 1475-85.
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  to examine the effects of socially enriched versus socially impoverished environments on performance and alertness decline during sleep deprivation in extraverts versus introverts.
• Rupp, T., Killgore, W., & Balkin, T. (2010). Vulnerability to sleep deprivation is differentially mediated by social exposure in extraverts versus introverts. Journal of Sleep Research, 19, 60.
• Killgore, W. D., Grugle, N. L., Reichardt, R. M., Killgore, D. B., & Balkin, T. J. (2009). Executive functions and the ability to sustain vigilance during sleep loss. Aviation, space, and environmental medicine, 80(2), 81-7.
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  There is considerable individual variability in the ability to sustain performance during sleep loss. Preliminary evidence suggests that individuals with higher trait-like activation/functioning of the prefrontal cortex may be less vulnerable to fatigue.
• Killgore, W. D., Kahn-Greene, E. T., Grugle, N. L., Killgore, D. B., & Balkin, T. J. (2009). Sustaining executive functions during sleep deprivation: A comparison of caffeine, dextroamphetamine, and modafinil. Sleep, 32(2), 205-16.
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  Stimulant medications appear effective at restoring simple alertness and psychomotor vigilance in sleep deprived individuals, but it is not clear whether these medications are effective at restoring higher order complex cognitive capacities such as planning, sequencing, and decision making.
• Killgore, W. D., Lipizzi, E. L., Grugle, N. L., Killgore, D. B., & Balkin, T. J. (2009). Handedness correlates with actigraphically measured sleep in a controlled environment. Perceptual and motor skills, 109(2), 395-400.
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  The relationship between hand preference and duration of sleep was assessed in 40 healthy subjects using self-report estimates, sleep diaries, and wrist activity monitors during an uncontrolled 7-day at-home phase and during a controlled overnight stay in a sleep laboratory. Handedness was unrelated to any index of sleep duration when assessed in the unregulated home environment. In the controlled environment of the laboratory, however, greater right-hand dominance was positively correlated with more minutes of obtained sleep and greater sleep efficiency. Findings were consistent with previous reports which suggest measures of brain lateralization may be related to sleep and health but further suggest that these relationships may be easily obscured by extraneous environmental factors when assessed in an uncontrolled setting.
• Killgore, W. D., Rosso, I. M., Gruber, S. A., & Yurgelun-Todd, D. A. (2009). Amygdala volume and verbal memory performance in schizophrenia and bipolar disorder. Cognitive and behavioral neurology : official journal of the Society for Behavioral and Cognitive Neurology, 22(1), 28-37.
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  To clarify the relationship between amygdala-hippocampal volume and cognitive performance in schizophrenia and bipolar disorder.
• Killgore, W., Kahn-Greene, E. T., Grugle, N. L., Killgore, D. B., & Balkin, T. J. (2009). Sustaining Executive Functions During Sleep Deprivation: A Comparison of Caffeine, Dextroamphetamine, and Modafinil. SLEEP, 32(2), 205-216.
• Picchioni, D., Killgore, W. D., Balkin, T. J., & Braun, A. R. (2009). Positron emission tomography correlates of visually-scored electroencephalographic waveforms during non-Rapid Eye Movement sleep. The International journal of neuroscience, 119(11), 2074-99.
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  Visually-scored, non-Rapid Eye Movement (REM) sleep electroencephalographic (EEG) waveform activity for each 30-s sleep scored epoch-including the number of sleep spindles, the number of K-complexes, and the percentage of delta waves occupying the epoch-was correlated with H(2)(15)O positron emission tomography. Sleep spindle correlations included positive correlations in the thalamus and right hippocampus. K-complex correlations included positive correlations in the frontomedian prefrontal cortex and cerebellum. Delta wave correlations included negative correlations in the thalamus, frontomedian prefrontal cortex, dorsal pons, and primary visual cortex. Each pattern of correlations may suggest a functional significance for these waveforms that relates to a waking outcome.
• Huck, N. O., McBride, S. A., Kendall, A. P., Grugle, N. L., & Killgore, W. D. (2008). The effects of modafinil, caffeine, and dextroamphetamine on judgments of simple versus complex emotional expressions following sleep deprivation. The International journal of neuroscience, 118(4), 487-502.
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  Cognitive abilities such as vigilance, attention, memory, and executive functioning can be degraded significantly following extended periods of wakefulness. Although much evidence suggests that sleep-loss induced deficits in alertness and vigilance can be reversed or mitigated by stimulants such as caffeine, it is not clear how these compounds may affect other higher level cognitive processes such as emotional perception and judgment. Following 47 h of sleep deprivation, the study examined the effect of three stimulant medications (modafinil 400 mg, dextroamphetamine 20 mg, caffeine 600 mg) or placebo on the ability of 54 healthy participants to discriminate and label simple emotional expressions versus complex affect blends (created by morphing photographs of two different affective facial expressions). For simple affective faces, neither sleep loss nor stimulant medications made any difference on the accuracy of judgments. In contrast, for complex emotion blends, all three stimulant medications significantly improved the ability to discriminate subtle aspects of emotion correctly relative to placebo, but did not differ from one another. These findings suggest that all three stimulant medications are effective at restoring some aspects of subtle affective perception.
• Killgore, W. D., Cotting, D. I., Thomas, J. L., Cox, A. L., McGurk, D., Vo, A. H., Castro, C. A., & Hoge, C. W. (2008). Post-combat invincibility: violent combat experiences are associated with increased risk-taking propensity following deployment. Journal of psychiatric research, 42(13), 1112-21.
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  Combat exposure is associated with increased rates of mental health problems such as post-traumatic stress disorder, depression, and anxiety when Soldiers return home. Another important health consequence of combat exposure involves the potential for increased risk-taking propensity and unsafe behavior among returning service members. Survey responses regarding 37 different combat experiences were collected from 1252 US Army Soldiers immediately upon return home from combat deployment during Operation Iraqi Freedom. A second survey that included the Evaluation of Risks Scale (EVAR) and questions about recent risky behavior was administered to these same Soldiers 3 months after the initial post-deployment survey. Combat experiences were reduced to seven factors using principal components analysis and used to predict post-deployment risk-propensity scores. Although effect sizes were small, specific combat experiences, including greater exposure to violent combat, killing another person, and contact with high levels of human trauma, were predictive of greater risk-taking propensity after homecoming. Greater exposure to these combat experiences was also predictive of actual risk-related behaviors in the preceding month, including more frequent and greater quantities of alcohol use and increased verbal and physical aggression toward others. Exposure to violent combat, human trauma, and having direct responsibility for taking the life of another person may alter an individual's perceived threshold of invincibility and slightly increase the propensity to engage in risky behavior upon returning home after wartime deployment. Findings highlight the importance of education and counseling for returning service members to mitigate the public health consequences of elevated risk-propensity associated with combat exposure.
• Killgore, W. D., Gruber, S. A., & Yurgelun-Todd, D. A. (2008). Abnormal corticostriatal activity during fear perception in bipolar disorder. Neuroreport, 19(15), 1523-7.
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  The time course of responses to repeated presentations of affective stimuli is well characterized in healthy individuals but remains to be characterized in patients with bipolar disorder. Using functional magnetic resonance imaging, we compared early-stage and late-stage brain activation during a two-block fearful face perception task in 14 adult bipolar patients to that of 13 healthy controls. Whereas control participants showed increased orbitofrontal, anterior cingulate, and striatum activity during the late (vs. early) stage of the task, bipolar patients failed to show normal task-related activity in these regions. Results suggest that bipolar disorder may involve corticostriatal dysfunction.
• Killgore, W. D., Grugle, N. L., Killgore, D. B., Leavitt, B. P., Watlington, G. I., McNair, S., & Balkin, T. J. (2008). Restoration of risk-propensity during sleep deprivation: caffeine, dextroamphetamine, and modafinil. Aviation, space, and environmental medicine, 79(9), 867-74.
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  Sleep deprivation alters risk-related judgments, decision-making, and behavioral control. Stimulant medications are used to restore cognitive performance, but their effects on risk-taking and judgment in sleep-deprived subjects have not been explored.
• Killgore, W. D., Kahn-Greene, E. T., Lipizzi, E. L., Newman, R. A., Kamimori, G. H., & Balkin, T. J. (2008). Sleep deprivation reduces perceived emotional intelligence and constructive thinking skills. Sleep medicine, 9(5), 517--526.
• Killgore, W. D., Kahn-Greene, E. T., Lipizzi, E. L., Newman, R. A., Kamimori, G. H., & Balkin, T. J. (2008). Sleep deprivation reduces perceived emotional intelligence and constructive thinking skills. Sleep medicine, 9(5), 517-26.
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  Insufficient sleep can adversely affect a variety of cognitive abilities, ranging from simple alertness to higher-order executive functions. Although the effects of sleep loss on mood and cognition are well documented, there have been no controlled studies examining its effects on perceived emotional intelligence (EQ) and constructive thinking, abilities that require the integration of affect and cognition and are central to adaptive functioning.
• Killgore, W. D., Killgore, D. B., McBride, S. A., Kamimori, G. H., & Balkin, T. J. (2008). Odor identification ability predicts changes in symptoms of psychopathology following 56 H of sleep deprivation. Journal of Sensory Studies, 23(1), 35--51.
• Killgore, W. D., McBride, S. A., Killgore, D. B., Balkin, T. J., & Kamimori, G. H. (2008). Baseline odor identification ability predicts degradation of psychomotor vigilance during 77 hours of sleep deprivation. The International journal of neuroscience, 118(9), 1207-25.
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  Scores on the University of Pennsylvania Smell Identification Test, a measure of the functional integrity of the orbitofrontal cortex, were used to predict the vulnerability to cognitive declines during 77 hr of sleep deprivation. Twenty-one healthy volunteers completed the Smell Identification Test at rested baseline followed by repeated psychomotor vigilance testing throughout each night. Participants with better smell identification abilities sustained faster speeds and fewer lapses on the second and third nights of sleep deprivation than participants with lower scores. Individual differences in trait-like functioning of the orbitofrontal cortex are predictive of the ability to sustain alertness and vigilance during continuous wakefulness.
• Killgore, W. D., Muckle, A. E., Grugle, N. L., Killgore, D. B., & Balkin, T. J. (2008). Sex differences in cognitive estimation during sleep deprivation: effects of stimulant countermeasures. The International journal of neuroscience, 118(11), 1547-57.
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  Stimulant medications restore simple alertness during sleep loss, but it is not clear how they affect complex executive functions, particularly in light of sex differences in cerebral organization. The effectiveness of caffeine, modafinil, dextroamphetamine, or placebo for sustaining performance on the Biber Cognitive Estimation Test (BCET) was compared in 29 men and 25 women following 46 hr of sleep deprivation. Stimulants had differential effects on BCET performance as a function of the sex of the subjects. Women receiving placebo or caffeine scored significantly worse than males, while modafinil and dextroamphetamine were effective at sustaining BCET performance of men and women.
• Killgore, W. D., Rupp, T. L., Grugle, N. L., Reichardt, R. M., Lipizzi, E. L., & Balkin, T. J. (2008). Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness. Journal of sleep research, 17(3), 309-21.
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  Prolonged sleep loss impairs alertness, vigilance and some higher-order cognitive and affective capacities. Some deficits can be temporarily reversed by stimulant medications including caffeine, dextroamphetamine, and modafinil. To date, only one study has directly compared the effectiveness of these three compounds and specified the doses at which all were equally effective in restoring alertness and vigilance following 64 h of wakefulness. The present study compared the effectiveness of these same three stimulants/doses following a less extreme period of sleep loss (i.e., 44 h). Fifty-three healthy adults received a single dose of modafinil 400 mg (n = 11), dextroamphetamine 20 mg (n = 16), caffeine 600 mg (n = 12), or placebo (n = 14) after 44 h of continuous wakefulness. After 61 h of being awake, participants obtained 12 h of recovery sleep. Psychomotor vigilance was assessed bi-hourly during waking and following recovery sleep. Relative to placebo, all three stimulants were equally effective in restoring psychomotor vigilance test speed and reducing lapses, although the duration of action was shortest for caffeine and longest for dextroamphetamine. At these doses, caffeine was associated with the highest percentage of subjectively reported side-effects while modafinil did not differ significantly from placebo. Subsequent recovery sleep was adversely affected in the dextroamphetamine group, but none of the stimulants had deleterious effects on postrecovery performance. Decisions regarding stimulant selection should be made with consideration of how factors such as duration of action, potential side-effects, and subsequent disruption of recovery sleep may interact with the demands of a particular operational environment.
• Killgore, W., Cotting, D. I., Thomas, J. L., Cox, A. L., McGurk, D., Vo, A. H., Castro, C. A., & Hoge, C. W. (2008). Post-combat invincibility: Violent combat experiences are associated with increased risk-taking propensity following deployment. JOURNAL OF PSYCHIATRIC RESEARCH, 42(13), 1112-1121.
• Killgore, W., Grugle, N. L., Killgore, D. B., Leavitt, B. P., Watlington, G. I., McNair, S., & Balkin, T. J. (2008). Restoration of risk-propensity during sleep deprivation: Caffeine, dextroamphetamine, and modafinil. AVIATION SPACE AND ENVIRONMENTAL MEDICINE, 79(9), 867-874.
• Killgore, W., Rupp, T. L., Grugle, N. L., Reichardt, R. M., Lipizzi, E. L., & Balkin, T. J. (2008). Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness. JOURNAL OF SLEEP RESEARCH, 17(3), 309-321.
• Adam, G., Szelenyi, E., Killgore, W., & Lieberman, H. (2007). A DOUBLE-BLIND STUDY OF TWO DAYS OF CALORIC DEPRIVATION: EFFECTS ON JUDGMENT AND DECISION-MAKING. AVIATION SPACE AND ENVIRONMENTAL MEDICINE, 78(3), 513.
• Kahn-Greene, E. T., Killgore, D. B., Kamimori, G. H., Balkin, T. J., & Killgore, W. (2007). The effects of sleep deprivation on symptoms of psychopathology in healthy adults. SLEEP MEDICINE, 8(3), 215-221.
• Kahn-Greene, E. T., Killgore, D. B., Kamimori, G. H., Balkin, T. J., & Killgore, W. D. (2007). The effects of sleep deprivation on symptoms of psychopathology in healthy adults. Sleep medicine, 8(3), 215-21.
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  Sleep loss leads to temporary changes in mood and cognition, and is associated with reduced cerebral metabolism within the prefrontal cortex, similar to findings observed in some psychiatric disorders. However, the extent to which sleep deprivation may be associated with the emergence of clinical symptoms of psychopathology in healthy normal individuals is not clear.
• Killgore, W. (2007). Effects of sleep deprivation and morningness-eveningness traits on risk-taking. PSYCHOLOGICAL REPORTS, 100(2), 613-626.
• Killgore, W. D. (2007). Effects of sleep deprivation and morningness-eveningness traits on risk-taking. Psychological reports, 100(2), 613-26.
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  Individuals differ along a continuum of preference for diurnal activity level, known as Morningness-Eveningness. Individuals low in Morningness traits, i.e., preferring later awakening and bed times, have been shown to score higher on personality traits of impulsiveness and novelty-seeking. No studies have yet examined the association between Morningness-Eveningness and the related construct of risk-taking. Therefore, the present study examined (1) whether Morningness was correlated with self-reported and behavioral measures of risk-taking, and (2) whether one night of sleep deprivation would produce changes in risk-taking and sensation-seeking. 54 healthy adults were administered the Morningness-Eveningness Questionnaire at intake, and administered the Brief Sensation Seeking Scale, Evaluation of Risks Scale, and Balloon Analog Risk Task at rested baseline, again following 23 hr. of sleep deprivation, and finally after a 12-hr. period of recovery sleep. Lower Morningness scores were associated with higher self-reported total risk-taking propensity when rested (p< .05) and sleep deprived (p
• Killgore, W. D., & Killgore, D. B. (2007). Morningness-eveningness correlates with verbal ability in women but not men. Perceptual and motor skills, 104(1), 335-8.
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  Individuals differ along a continuum of preference for diurnal activity level, known as Morningness-Eveningness. Some evidence suggests that an Eveningness orientation (i.e., preference for later rise and bed times) is weakly associated with higher cognitive ability, but no studies have examined this relationship using clinically accepted, psychometrically valid measures of cognitive ability. The present study examined the correlation between Morningness-Eveningness with scores on the Wechsler Abbreviated Scale of Intelligence (WASI) of 54 healthy volunteers. Lower Morningness (i.e., Greater Eveningness) orientation was correlated (r = -.23) with higher Verbal IQ for the entire sample. When the data were examined separately by sex, the correlation between Morningness-Eveningness and Verbal IQ was significant for women (r = -.44) but not for men (r = -.09).
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). Neural correlates of emotional intelligence in adolescent children. Cognitive, Affective, \& Behavioral Neuroscience, 7(2), 140--151.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). Neural correlates of emotional intelligence in adolescent children. Cognitive, affective & behavioral neuroscience, 7(2), 140-51.
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  The somatic marker hypothesis posits a key role for the ventromedial prefrontal cortex, amygdala, and insula in the ability to utilize emotions to guide decision making and behavior. However, the relationship between activity in these brain regions and emotional intelligence (EQ) during adolescence, a time of particular importance for emotional and social development, has not been studied. Using functional magnetic resonance imaging (fMRI), we correlated scores from the Bar-On Emotional Quotient Inventory, Youth Version (EQ-i:YV) with brain activity during perception of fearful faces in 16 healthy children and adolescents. Consistent with the neural efficiency hypothesis, higher EQ correlated negatively with activity in the somatic marker circuitry and other paralimbic regions. Positive correlations were observed between EQ and activity in the cerebellum and visual association cortex. The findings suggest that the construct of self-reported EQ in adolescents is inversely related to the efficiency of neural processing within the somatic marker circuitry during emotional provocation.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). Positive affect modulates activity in the visual cortex to images of high calorie foods. The International journal of neuroscience, 117(5), 643-53.
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  Activity within the visual cortex can be influenced by the emotional salience of a stimulus, but it is not clear whether such cortical activity is modulated by the affective status of the individual. This study used functional magnetic resonance imaging (fMRI) to examine the relationship between affect ratings on the Positive and Negative Affect Schedule and activity within the occipital cortex of 13 normal-weight women while viewing images of high calorie and low calorie foods. Regression analyses revealed that when participants viewed high calorie foods, Positive Affect correlated significantly with activity within the lingual gyrus and calcarine cortex, whereas Negative Affect was unrelated to visual cortex activity. In contrast, during presentations of low calorie foods, affect ratings, regardless of valence, were unrelated to occipital cortex activity. These findings suggest a mechanism whereby positive affective state may affect the early stages of sensory processing, possibly influencing subsequent perceptual experience of a stimulus.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). The right-hemisphere and valence hypotheses: could they both be right (and sometimes left)?. Social cognitive and affective neuroscience, 2(3), 240--250.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). The right-hemisphere and valence hypotheses: could they both be right (and sometimes left)?. Social cognitive and affective neuroscience, 2(3), 240-50.
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  The two halves of the brain are believed to play different roles in emotional processing, but the specific contribution of each hemisphere continues to be debated. The right-hemisphere hypothesis suggests that the right cerebrum is dominant for processing all emotions regardless of affective valence, whereas the valence specific hypothesis posits that the left hemisphere is specialized for processing positive affect while the right hemisphere is specialized for negative affect. Here, healthy participants viewed two split visual-field facial affect perception tasks during functional magnetic resonance imaging, one presenting chimeric happy faces (i.e. half happy/half neutral) and the other presenting identical sad chimera (i.e. half sad/half neutral), each masked immediately by a neutral face. Results suggest that the posterior right hemisphere is generically activated during non-conscious emotional face perception regardless of affective valence, although greater activation is produced by negative facial cues. The posterior left hemisphere was generally less activated by emotional faces, but also appeared to recruit bilateral anterior brain regions in a valence-specific manner. Findings suggest simultaneous operation of aspects of both hypotheses, suggesting that these two rival theories may not actually be in opposition, but may instead reflect different facets of a complex distributed emotion processing system.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2007). Unconscious processing of facial affect in children and adolescents. Social neuroscience, 2(1), 28-47.
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  In a previous study, with adults, we demonstrated that the amygdala and anterior cingulate gyrus are differentially responsive to happy and sad faces presented subliminally. Because the ability to perceive subtle facial signals communicating sadness is an important aspect of prosocial development, and is critical for empathic behavior, we examined this phenomenon from a developmental perspective using a backward masking paradigm. While undergoing functional magnetic resonance imaging (fMRI), 10 healthy adolescent children were presented with a series of happy and sad facial expressions, each lasting 20 ms and masked immediately by a neutral face to prevent conscious awareness of the affective expression. Relative to fixation baseline, masked sad faces activated the right amygdala, whereas masked happy faces failed to activate any of the regions of interest. Direct comparison between masked happy and sad faces revealed valence specific differences in the anterior cingulate gyrus. When the data were compared statistically to our previous sample of adults, the adolescent group showed significantly greater activity in the right amygdala relative to the adults during the masked sad condition. Groups also differed in several non-hypothesized regions. Development of unconscious perception from adolescence into adulthood appears to be accompanied by reduced activity within limbic affect processing systems, and perhaps increased involvement of other cortical and cerebellar systems.
• Killgore, W. D., Gruber, S. A., & Yurgelun-Todd, D. A. (2007). Depressed mood and lateralized prefrontal activity during a Stroop task in adolescent children. Neuroscience letters, 416(1), 43-8.
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  Negative affective style and depressive disorders share a common pattern of brain activation asymmetry in adults, characterized by reduced left relative to right prefrontal activation. It is not clear whether a similar pattern of asymmetry is related to depressive mood state during the period of adolescence, an important stage of emotional and brain development. We correlated Beck Depression Inventory (BDI) scores from 16 adolescents with prefrontal, anterior cingulate, and amygdala activity during functional magnetic resonance imaging (FMRI) of the Stroop Interference task. Depressed mood correlated positively with activity in the left dorsolateral prefrontal cortex (DLPFC) and anterior cingulate gyrus, and negatively with activity in the right DLPFC. When interpreted from a compensatory recruitment perspective, findings suggest that affective lateralization in adolescents is consistent with that seen in adulthood.
• Killgore, W. D., Kahn-Greene, E. T., Killgore, D. B., Kamimori, G. H., & Balkin, T. J. (2007). Effects of acute caffeine withdrawal on Short Category Test performance in sleep-deprived individuals. Perceptual and motor skills, 105(3 Pt 2), 1265-74.
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  Caffeine is a popular stimulant often used to counter the effects of sleep loss and fatigue. Withdrawal from caffeine may produce mild declines in simple cognitive capacities such as attention and concentration, but it is unclear whether more complex cognitive functions, such as abstract reasoning or concept formation, may be similarly affected. To assess the effect of acute caffeine withdrawal on executive functioning during sleep deprivation, 26 healthy volunteers were administered in double-blind form either repeated doses of caffeine or placebo over two nights of continuous wakefulness. The 108-item Short Category Test was administered after 56 hr. of total sleep deprivation (9 hr. post-caffeine administration). The caffeine group scored significantly more poorly, making approximately 57% more errors on the test than the placebo group. These findings suggest that acute caffeine withdrawal during prolonged sleep deprivation has an adverse effect on abstract reasoning and concept formation.
• Killgore, W. D., Kendall, A. P., Richards, J. M., & McBride, S. A. (2007). Lack of degradation in visuospatial perception of line orientation after one night of sleep loss. Perceptual and motor skills, 105(1), 276-86.
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  Sleep deprivation impairs a variety of cognitive abilities including vigilance, attention, and executive function. Although sleep loss has been shown to impair tasks requiring visual attention and spatial perception, it is not clear whether these deficits are exclusively a function of reduced attention and vigilance or if there are also alterations in visuospatial perception. Visuospatial perception and sustained vigilance performance were therefore examined in 54 healthy volunteers at rested baseline and again after one night of sleep deprivation using the Judgment of Line Orientation Test and a computerized test of psychomotor vigilance. Whereas psychomotor vigilance declined significantly from baseline to sleep-deprived testing, scores on the Judgment of Line Orientation did not change significantly. Results suggest that documented performance deficits associated with sleep loss are unlikely to be the result of dysfunction within systems of the brain responsible for simple visuospatial perception and processing of line angles.
• Killgore, W. D., Killgore, D. B., Day, L. M., Li, C., Kamimori, G. H., & Balkin, T. J. (2007). The effects of 53 hours of sleep deprivation on moral judgment. Sleep, 30(3), 345-52.
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  Functional neuroimaging studies suggest a prominent role for the medial prefrontal cortex in the formation of moral judgments. Activity in this region has also been shown to decline significantly during sleep loss. We therefore examined the effects of 2 nights of sleep deprivation on several aspects of moral judgment.
• Killgore, W. D., Killgore, D. B., Day, L. M., Li, C., Kamimori, G. H., Balkin, T. J., & others, . (2007). The effects of 53 hours of sleep deprivation on moral judgment. SLEEP-NEW YORK THEN WESTCHESTER-, 30(3), 345.
• Killgore, W. D., Lipizzi, E. L., Kamimori, G. H., & Balkin, T. J. (2007). Caffeine effects on risky decision making after 75 hours of sleep deprivation. Aviation, space, and environmental medicine, 78(10), 957--962.
• Killgore, W. D., Lipizzi, E. L., Kamimori, G. H., & Balkin, T. J. (2007). Caffeine effects on risky decision making after 75 hours of sleep deprivation. Aviation, space, and environmental medicine, 78(10), 957-62.
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  Recent research indicates that sleep deprivation impairs decision making. However, it is unknown to what extent such deficits are exacerbated in a dose-response manner by increasing levels of sleepiness, and the extent to which such sleep-loss-induced deficits can be reversed by caffeine.
• Killgore, W. D., Richards, J. M., Killgore, D. B., Kamimori, G. H., & Balkin, T. J. (2007). The trait of Introversion-Extraversion predicts vulnerability to sleep deprivation. Journal of sleep research, 16(4), 354-63.
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  According to Eysenck's theory of Introversion-Extroversion (I-E), introverts demonstrate higher levels of basal activity within the reticular-thalamic-cortical loop, yielding higher tonic cortical arousal than Extraverts, who are described conversely as chronically under-aroused and easily bored. We hypothesized that higher scores on the trait of Extraversion would be associated with greater declines in psychomotor vigilance performance during prolonged wakefulness. We evaluated the relationship between I-E and overnight psychomotor vigilance performance during 77 h of continuous sleep deprivation in a sample of 23 healthy adult military personnel (19 men; four women), ranging in age from 20 to 35 years. At baseline, volunteers completed the Revised NEO Personality Inventory (NEO PI-R) and completed psychomotor vigilance testing at approximately 10-min intervals from 00:15 to 08:50 hours over three nights of continuous sleep deprivation. In addition, 12 participants received four repeated administrations of caffeine (200 mg) every 2 h each night. Analysis of covariance and stepwise multiple regression analyses showed that, above and beyond the effects of caffeine, higher Extraversion was significantly related to more extensive declines in speed of responding and more frequent attentional lapses, but only for the first overnight testing session. Sub-factors of Extraversion, including Gregariousness and higher Activity level were most predictive of these changes following sleep loss. These findings are consistent with Eysenck's cortico-reticular activation theory of I-E and suggest that individual differences in the trait of Extraversion confer some vulnerability/resistance to the adverse effects of sleep loss on attention and vigilance.
• Killgore, W., & Yurgelun-Todd, D. A. (2007). Unconscious processing of facial affect in children and adolescents. SOCIAL NEUROSCIENCE, 2(1), 28-47.
• Killgore, W., Gruber, S. A., & Yurgelun-Todd, D. A. (2007). Depressed mood and lateralized prefrontal activity during a Stroop task in adolescent children. NEUROSCIENCE LETTERS, 416(1), 43-48.
• Rosso, I. M., Killgore, W. D., Cintron, C. M., Gruber, S. A., Tohen, M., & Yurgelun-Todd, D. A. (2007). Reduced amygdala volumes in first-episode bipolar disorder and correlation with cerebral white matter. Biological psychiatry, 61(6), 743-9.
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  Previous magnetic resonance imaging (MRI) findings on amygdala volume abnormalities in bipolar disorder have been inconsistent, which may partly reflect clinical heterogeneity. It is unclear whether amygdala abnormalities are present early in the course of illness and/or are the consequence of disease progression.
• Rosso, I. M., Killgore, W., Cintron, C. M., Gruber, S. A., Tohen, M., & Yurgelun-Todd, D. A. (2007). Reduced amygdala volumes in first-episode bipolar disorder and correlation with cerebral white matter. BIOLOGICAL PSYCHIATRY, 61(6), 743-749.
• Vo, A. H., Satori, R., Jabbari, B., Green, J., Killgore, W. D., Labutta, R., & Campbell, W. W. (2007). Botulinum toxin type-a in the prevention of migraine: a double-blind controlled trial. Aviation, space, and environmental medicine, 78(5 Suppl), B113-8.
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  Migraine is a frequent medical complaint. In military populations, migraine can be detrimental to productivity and troop readiness, and can be disqualifying for service in some military duty specialties. This study assessed the effectiveness of botulinum neurotoxin type-A (BTX-A) in reducing the frequency of migraines in known migraineurs.
• Kahn-Greene, E. T., Lipizzi, E. L., Conrad, A. K., Kamimori, G. H., & Killgore, W. (2006). Sleep deprivation adversely affects interpersonal responses to frustration. PERSONALITY AND INDIVIDUAL DIFFERENCES, 41(8), 1433-1443.
• Kahn-Greene, E. T., Lipizzi, E. L., Conrad, A. K., Kamimori, G. H., & Killgore, W. D. (2006). Sleep deprivation adversely affects interpersonal responses to frustration. Personality and Individual Differences, 41(8), 1433--1443.
• Kendall, A. P., Kautz, M. A., Russo, M. B., & Killgore, W. D. (2006). Effects of sleep deprivation on lateral visual attention. The International journal of neuroscience, 116(10), 1125-38.
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  Sleep loss temporarily impairs vigilance and sustained attention. Because these cognitive abilities are believed to be mediated predominantly by the right cerebral hemisphere, this article hypothesized that continuous sleep deprivation results in a greater frequency of inattention errors within the left versus right visual fields. Twenty-one participants were assessed several times each day during a 40-h period of sustained wakefulness and following a night of recovery sleep. At each assessment, participants engaged in a continuous serial addition task while simultaneously monitoring a 150 degrees visual field for brief intermittent flashes of light. Overall, omission errors were most common in the leftmost peripheral field for all sessions, and did not show any evidence of a shift in laterality as a function of sleep deprivation. Relative to rested baseline and postrecovery conditions, sleep deprivation resulted in a global increase in omission errors across all visual locations and a general decline in serial addition performance. These findings argue against the hypothesis that sleep deprivation produces lateralized deficits in attention and suggest instead that deficits in visual attention produced by sleep deprivation are global and bilateral in nature.
• Killgore, W. D., & McBride, S. A. (2006). Odor identification accuracy declines following 24 h of sleep deprivation. Journal of sleep research, 15(2), 111-6.
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  Brain imaging studies demonstrate that sleep deprivation reduces glucose metabolism and blood flow in the prefrontal cortex, and such reductions are associated with impairments in cognitive functioning. Although some of the greatest metabolic declines occur within the orbitofrontal cortex, little is known about the effects of sleep loss on the types of processes mediated by this region, including emotion, motivation, feeding, and olfaction. The present study tested odor identification accuracy when individuals were well rested and again following 24 h of wakefulness. Relative to rested baseline performance, sleep-deprived individuals demonstrated a significant decline in the ability to identify specific odors on the Smell Identification Test. This decrement in olfactory functioning occurred concomitantly with slowed psychomotor speed and increased ratings of self-reported sleepiness. Performance on a task that required complex mental set shifting did not change significantly following sleep deprivation, suggesting that the decrements in odor identification could not be attributed to task difficulty. Finally, while there was no relationship between subjective sleepiness and odor identification at rested baseline, greater subjective sleepiness was associated with better odor identification ability following 24 h of sleep loss. Possible implications of these findings are discussed.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2006). Affect modulates appetite-related brain activity to images of food. The International journal of eating disorders, 39(5), 357-63.
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  We examined whether affect ratings predicted regional cerebral responses to high and low-calorie foods.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2006). Ventromedial prefrontal activity correlates with depressed mood in adolescent children. Neuroreport, 17(2), 167-71.
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  In adults, the medial prefrontal cortex and anterior cingulate gyrus are preferentially activated during emotion-related processes, including normal sadness and pathological depression. It is not clear, however, whether similar regional activity is also characteristic of depressed mood during adolescence. We correlated whole brain activity during a fear face perception task with scores on the Beck Depression Inventory in 16 adolescents undergoing functional magnetic resonance imaging. After controlling for age, depressed mood scores correlated with increased activity within the ventromedial prefrontal cortex and rostral anterior cingulate gyrus, consistent with findings previously reported for sadness and depression in adults, suggesting that the neural substrates of depressed mood are established early in life and remain relatively consistent across development into adulthood.
• Killgore, W. D., Balkin, T. J., & Wesensten, N. J. (2006). Impaired decision making following 49 h of sleep deprivation. Journal of sleep research, 15(1), 7--13.
• Killgore, W. D., Balkin, T. J., & Wesensten, N. J. (2006). Impaired decision making following 49 h of sleep deprivation. Journal of sleep research, 15(1), 7-13.
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  Sleep deprivation reduces regional cerebral metabolism within the prefrontal cortex, the brain region most responsible for higher-order cognitive processes, including judgment and decision making. Accordingly, we hypothesized that two nights of sleep loss would impair decision making quality and lead to increased risk-taking behavior on the Iowa Gambling Task (IGT), which mimics real-world decision making under conditions of uncertainty. Thirty-four healthy participants completed the IGT at rested baseline and again following 49.5 h of sleep deprivation. At baseline, volunteers performed in a manner similar to that seen in most samples of healthy normal individuals, rapidly learning to avoid high-risk decks and selecting more frequently from advantageous low-risk decks as the game progressed. After sleep loss, however, volunteers showed a strikingly different pattern of performance. Relative to rested baseline, sleep-deprived individuals tended to choose more frequently from risky decks as the game progressed, a pattern similar to, though less severe than, previously published reports of patients with lesions to the ventromedial prefrontal cortex. Although risky decision making was not related to participant age when tested at rested baseline, age was negatively correlated with advantageous decision making on the IGT, when tested following sleep deprivation (i.e. older subjects made more risky choices). These findings suggest that cognitive functions known to be mediated by the ventromedial prefrontal cortex, including decision making under conditions of uncertainty, may be particularly vulnerable to sleep loss and that this vulnerability may become more pronounced with increased age.
• Killgore, W. D., Killgore, D. B., Ganesan, G., Krugler, A. L., & Kamimori, G. H. (2006). Trait-anger enhances effects of caffeine on psychomotor vigilance performance. Perceptual and motor skills, 103(3), 883-6.
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  This study examined the combined effects of caffeine and the personality attribute of trait-anger on the speed of psychomotor vigilance performance during sleep deprivation. 23 young adult soldiers (19 male) were administered the State-Trait Anger Expression Inventory-2 when well-rested. Participants were then sleep deprived for three consecutive nights (77 hours total) during which they completed repeated psychomotor vigilance testing. Half of the participants received four doses of oral caffeine (200 mg every 2 hr.; 800 mg total) each night, while the other half were administered a placebo. For the first night, higher scores on trait-anger, outward anger expression, and intensity of anger expression predicted better sustained overnight vigilance performance, but only for those volunteers receiving caffeine. These correlations were not significant for the subsequent nights. Findings suggest a possible synergistic effect between personality traits associated with arousal of the central nervous system and vigilance-promoting effects of caffeine.
• Killgore, W. D., McBride, S. A., Killgore, D. B., & Balkin, T. J. (2006). The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation. SLEEP-NEW YORK THEN WESTCHESTER-, 29(6), 841.
• Killgore, W. D., McBride, S. A., Killgore, D. B., & Balkin, T. J. (2006). The effects of caffeine, dextroamphetamine, and modafinil on humor appreciation during sleep deprivation. Sleep, 29(6), 841-7.
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  Sleep loss consistently impairs performance on measures of alertness, vigilance, and response speed, but its effects on higher-order executive functions are not well delineated. Similarly, whereas deficits in arousal and vigilance can be temporarily countered by the use of several different stimulant medications, it is not clear how these compounds affect complex cognitive processes in sleep-deprived individuals.
• Killgore, W. D., Stetz, M. C., Castro, C. A., & Hoge, C. W. (2006). The effects of prior combat experience on the expression of somatic and affective symptoms in deploying soldiers. Journal of psychosomatic research, 60(4), 379--385.
• Killgore, W. D., Stetz, M. C., Castro, C. A., & Hoge, C. W. (2006). The effects of prior combat experience on the expression of somatic and affective symptoms in deploying soldiers. Journal of psychosomatic research, 60(4), 379-85.
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  Deployment to a combat zone is undoubtedly an extremely stressful experience. It was hypothesized that, when faced with an impending wartime deployment, soldiers with prior combat experience would report minimal emotional problems accompanied by high rates of somatic complaints compared with combat-naive soldiers.
• Killgore, W. D., Vo, A. H., Castro, C. A., & Hoge, C. W. (2006). Assessing risk propensity in American soldiers: preliminary reliability and validity of the Evaluation of Risks (EVAR) scale--English version. Military medicine, 171(3), 233-9.
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  Risk-taking propensity is a critical component of judgment and decision-making in military operations. The Evaluation of Risks scale (EVAR) was recently developed to measure state and trait aspects of risk proneness. The scale, however, was psychometrically normed in French and no data are available for the English translation. We administered the English version of the EVAR to 165 U.S. soldiers to obtain reliability, validity, and normative data for English-speaking respondents. Confirmatory factor analysis suggested that the factor structure of the English EVAR differs from that obtained in the French studies. Instead, a three-factor solution, including recklessness/impulsivity, self-confidence, and need for control, emerged. Internal consistency was comparable to the French version. EVAR scores correlated with age, military rank, and years of service, and discriminated soldiers with histories of high-risk behavior. The data support the reliability and validity of the English version of the EVAR for evaluating risk propensity in U.S. soldiers.
• Killgore, W., & McBride, S. A. (2006). Odor identification accuracy declines following 24 h of sleep deprivation. JOURNAL OF SLEEP RESEARCH, 15(2), 111-116.
• Killgore, W., & Yurgelun-Todd, D. (2006). Affect modulates appetite-related brain activity to images of food. INTERNATIONAL JOURNAL OF EATING DISORDERS, 39(5), 357-363.
• Killgore, W., & Yurgelun-Todd, D. (2006). Ventromedial prefrontal activity correlates with depressed mood in adolescent children. NEUROREPORT, 17(2), 167-171.
• Mcbride, S. A., Balkin, T. J., Kamimori, G. H., & Killgore, W. D. (2006). Olfactory decrements as a function of two nights of sleep deprivation. Journal of sensory studies, 21(4), 456--463.
• Yurgelun-Todd, D. A., & Killgore, W. (2006). Fear-related activity in the prefrontal cortex increases with age during adolescence: A preliminary fMRI study. NEUROSCIENCE LETTERS, 406(3), 194-199.
• Yurgelun-Todd, D. A., & Killgore, W. D. (2006). Fear-related activity in the prefrontal cortex increases with age during adolescence: a preliminary fMRI study. Neuroscience letters, 406(3), 194-9.
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  An emerging theory of adolescent development suggests that brain maturation involves a progressive "frontalization" of function whereby the prefrontal cortex gradually assumes primary responsibility for many of the cognitive processes initially performed by more primitive subcortical and limbic structures. To test the hypothesis of developmental frontalization in emotional processing, we analyzed the correlation between age and prefrontal cortex activity in a sample of 16 healthy adolescents (nine boys; seven girls), ranging in age from 8 to 15 years, as they viewed images of fearful and happy faces while undergoing functional magnetic resonance imaging (fMRI). During fear perception, age was significantly positively correlated with greater functional activity within the prefrontal cortex, whereas no significant relationship was evident between age and activity in the amygdala. Consistent with previous gender-related findings, age was significantly correlated with bilateral prefrontal activity for the sample of females, but was only significantly related to right prefrontal activity for the males. In contrast, similar age-related correlations were not evident during the perception of happy faces. These results suggest that the maturation of threat-related emotional processing during adolescence is related to the progressive acquisition of greater functional activity within the prefrontal cortex. The hypothesis of age related decreases in amygdala activity was not supported, but may have been due to low signal-to-noise and inadequate power in the present sample to resolve subtle changes in this small structure.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2005). Body mass predicts orbitofrontal activity during visual presentations of high-calorie foods. Neuroreport, 16(8), 859-63.
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  Little is known about the relationship between weight status and reward-related brain activity in normal weight humans. We correlated orbitofrontal and anterior cingulate cortex activity as measured by functional magnetic resonance imaging with body mass index in 13 healthy, normal-weight adult women as they viewed images of high-calorie and low-calorie foods, and dining-related utensils. Body mass index correlated negatively with both cingulate and orbitofrontal activity during high-calorie viewing, negatively with orbitofrontal activity during low-calorie viewing, and positively with orbitofrontal activity during presentations of nonedible utensils. With greater body mass, activity was reduced in brain regions important for evaluating and modifying learned stimulus-reward associations, suggesting a relationship between weight status and responsiveness of the orbitofrontal cortex to rewarding food images.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2005). Developmental changes in the functional brain responses of adolescents to images of high and low-calorie foods. Developmental psychobiology, 47(4), 377-97.
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  We examined cerebral responses to visually presented food images in children and adolescents. Eight healthy normal-weight females (ages 9-15) underwent functional magnetic resonance imaging (fMRI) while viewing photographs of high- and low-calorie foods and dining utensils. In general, food images yielded significant activation within the inferior orbitofrontal cortex, hippocampus, and fusiform gyri. High calorie food images activated the left hippocampus and subgenual cingulate, and age correlated positively with activity within the orbitofrontal cortex but negatively with activity within the anterior cingulate gyrus. Low-calorie foods activated the fusiform gyrus and demonstrated age-related increases in the left superior temporal gyrus and anterior cingulate. Utensils activated the fusiform gyrus and showed age-related increases in the prefrontal cortex. Data were also compared statistically to a sample of adults exposed to the same stimulus conditions. Findings support a developmental model of adolescent maturation whereby age-related changes in cerebral functioning develop from lower-order sensory processing toward higher-order processing of stimuli via prefrontal cortical systems involved in reward anticipation, self-monitoring, and behavioral inhibition.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2005). Social anxiety predicts amygdala activation in adolescents viewing fearful faces. Neuroreport, 16(15), 1671-5.
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  The amygdala is critically involved in the processing of anxiety in adults, but little is known about the neurogenesis of trait-anxiety during adolescence. We correlated amygdala activity during visual presentations of fearful and happy faces with scores on the Multidimensional Anxiety Scale for Children in 16 adolescents undergoing functional magnetic resonance imaging. During fear perception, amygdala activity positively correlated with several social dimensions of anxiety, including peer rejection, humiliation, performing in public, and being separated from loved ones, but was not correlated with most measured nonsocial dimensions of anxiety. Amygdala responses during happy face presentations correlated positively only with tension/restlessness. During adolescence, amygdala activity appears to be more strongly related to social/interpersonal than nonsocial dimensions of anxiety.
• Killgore, W. D., Glahn, D. C., & Casasanto, D. J. (2005). Development and Validation of the Design Organization Test (DOT): a rapid screening instrument for assessing visuospatial ability. Journal of clinical and experimental neuropsychology, 27(4), 449-59.
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  A brief paper-and-pencil instrument was developed to rapidly assess visuospatial ability and serve as an alterative to the WAIS Block Design subtests during screening or when assessment time is limited. The Design Organization Test (DOT) consists of square black-and-white grids with visual patterns similar to those of the Block Design subtests. Administration is straightforward and requires examinees to reproduce as many designs as possible in 2 minutes using a numerical code key. For 411 college students, alternate forms of the DOT yielded reliability estimates comparable to that of the test-retest reliability of WAIS-III Block Design subtest. In a clinical sample, the DOT was significantly correlated (r = .92) with WAIS-III Block Design scores and was successfully substituted in place of Block Design raw scores without significant change in Performance IQ or Full Scale IQ. The results suggest that the DOT provides a useful and rapid screening measure of visuospatial ability.
• Killgore, W., & Yurgelun-Todd, D. (2005). Body mass predicts orbitofrontal activity during visual presentations of high-calorie foods. NEUROREPORT, 16(8), 859-863.
• Killgore, W., & Yurgelun-Todd, D. (2005). Developmental changes in the functional brain responses of adolescents to images of high and low-calorie foods. DEVELOPMENTAL PSYCHOBIOLOGY, 47(4), 377-397.
• Killgore, W., & Yurgelun-Todd, D. (2005). Social anxiety predicts amygdala activation in adolescents viewing fearful faces. NEUROREPORT, 16(15), 1671-1675.
• Wesensten, N. J., Killgore, W. D., & Balkin, T. J. (2005). Performance and alertness effects of caffeine, dextroamphetamine, and modafinil during sleep deprivation. Journal of sleep research, 14(3), 255-66.
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  Stimulants may provide short-term performance and alertness enhancement during sleep loss. Caffeine 600 mg, d-amphetamine 20 mg, and modafinil 400 mg were compared during 85 h of total sleep deprivation to determine the extent to which the three agents restored performance on simple psychomotor tasks, objective alertness and tasks of executive functions. Forty-eight healthy young adults remained awake for 85 h. Performance and alertness tests were administered bi-hourly from 8:00 hours day 2 to 19:00 hours day 5. At 23:50 hours on day 4 (after 64 h awake), subjects ingested placebo, caffeine 600 mg, dextroamphetamine 20 mg, or modafinil 400 mg (n=12 per group). Performance and alertness testing continued, and probe tasks of executive function were administered intermittently until the recovery sleep period (20:00 hours day 5 to 8:00 hours day 5). Bi-hourly postrecovery sleep testing occurred from 10:00 hours to 16:00 hours day 6. All three agents improved psychomotor vigilance speed and objectively measured alertness relative to placebo. Drugs did not affect recovery sleep, and postrecovery sleep performance for all drug groups was at presleep deprivation levels. Effects on executive function tasks were mixed, with improvement on some tasks with caffeine and modafinil, and apparent decrements with dextroamphetamine on others. At the doses tested, caffeine, dextroamphetamine, and modafinil are equally effective for approximately 2-4 h in restoring simple psychomotor performance and objective alertness. The duration of these benefits vary in accordance with the different elimination rates of the drugs. Whether caffeine, dextroamphetamine, and modafinil differentially restore executive functions during sleep deprivation remains unclear.
• Wesensten, N. J., Killgore, W., & Balkin, T. J. (2005). Performance and alertness effects of caffeine, dextro amphetamine, and modafinil during sleep deprivation. JOURNAL OF SLEEP RESEARCH, 14(3), 255-266.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2004). Activation of the amygdala and anterior cingulate during nonconscious processing of sad versus happy faces. NeuroImage, 21(4), 1215-23.
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  Previous functional neuroimaging studies have demonstrated that the amygdala activates in response to fearful faces presented below the threshold of conscious visual perception. Using a backward masking procedure similar to that of previous studies, we used functional magnetic resonance imaging (fMRI) to study the amygdala and anterior cingulate gyrus during preattentive presentations of sad and happy facial affect. Twelve healthy adult females underwent blood oxygen level dependent (BOLD) fMRI while viewing sad and happy faces, each presented for 20 ms and "masked" immediately by a neutral face for 100 ms. Masked happy faces were associated with significant bilateral activation within the anterior cingulate gyrus and amygdala, whereas masked sadness yielded only limited activation within the left anterior cingulate gyrus. In a direct comparison, masked happy faces yielded significantly greater activation in the anterior cingulate and amygdala relative to identically masked sad faces. Conjunction analysis showed that masked affect perception, regardless of emotional valence, was associated with greater activation within the left amygdala and left anterior cingulate. Findings suggest that the amygdala and anterior cingulate are important components of a network involved in detecting and discriminating affective information presented below the normal threshold of conscious visual perception.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2004). Sex-related developmental differences in the lateralized activation of the prefrontal cortex and amygdala during perception of facial affect. Perceptual and motor skills, 99(2), 371-91.
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  The lateralization of cognitive abilities is influenced by a number of factors, including handedness, sex, and developmental maturation. To date, a small number of studies have examined sex differences in the lateralization of cognitive and affective functions, and in only few of these have the developmental trajectories of these lateralized differences been mapped from childhood through early adulthood. In the present study, a cross-sectional design was used with healthy children (n=7), adolescents (n= 12), and adults (n= 10) who underwent functional magnetic resonance imaging (fMRI) during a task that required perceiving fearful faces. Males and females differed in the asymmetry of activation of the amygdala and prefrontal cortex across the three age groups. For males, activation within the dorsolateral prefrontal cortex was bilateral in children, right lateralized in adolescents, and bilateral in adults, whereas females showed a monotonic relationship with age, with older females showing more bilateral activation than younger ones. In contrast, amygdala activation was similar for both sexes, with bilateral activation in children, right-lateralized activation in adolescents, and bilateral activation in adults. These results suggest that males and females show different patterns of lateralized cortical and subcortical brain activation across the period of development from childhood through early adulthood.
• Killgore, W., & Yurgelun-Todd, D. (2004). Activation of the amygdala and interior cingulate during nonconscious processing of sad versus happy faces. NEUROIMAGE, 21(4), 1215-1223.
• Killgore, W., & Yurgelun-Todd, D. (2004). Sex-related developmental differences in the lateralized activation of the prefrontal cortex and amygdala during perception of facial affect. PERCEPTUAL AND MOTOR SKILLS, 99(2), 371-391.
• Wesensten, N., Killgore, W., Belenky, G., Reichardt, R., Thorne, D., & Balkin, T. (2004). Caffeine, Dextroamphetamine, And Modafinil During 85 H Of Sleep Deprivation. Ii. Effects On Tasks Of Executive Function. Journal of Sleep Research, Supplement, 13, 1.
• Killgore, W. D., Young, A. D., Femia, L. A., Bogorodzki, P., Rogowska, J., & Yurgelun-Todd, D. A. (2003). Cortical and limbic activation during viewing of high- versus low-calorie foods. NeuroImage, 19(4), 1381-94.
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  Despite the high prevalence of obesity, eating disorders, and weight-related health problems in modernized cultures, the neural systems regulating human feeding remain poorly understood. Therefore, we applied functional magnetic resonance imaging (fMRI) to study the cerebral responses of 13 healthy normal-weight adult women as they viewed color photographs of food. The motivational salience of the stimuli was manipulated by presenting images from three categories: high-calorie foods, low-calorie foods, and nonedible dining-related utensils. Both food categories were associated with bilateral activation of the amygdala and ventromedial prefrontal cortex. High-calorie foods yielded significant activation within the medial and dorsolateral prefrontal cortex, thalamus, hypothalamus, corpus callosum, and cerebellum. Low-calorie foods yielded smaller regions of focal activation within medial orbitofrontal cortex; primary gustatory/somatosensory cortex; and superior, middle, and medial temporal regions. Findings suggest that the amygdala may be responsive to a general category of biologically relevant stimuli such as food, whereas separate ventromedial prefrontal systems may be activated depending on the perceived reward value or motivational salience of food stimuli.
• Killgore, W. D., Young, A. D., Femia, L. A., Bogorodzki, P., Rogowska, J., & Yurgelun-Todd, D. A. (2003). Cortical and limbic activation during viewing of high-versus low-calorie foods. Neuroimage, 19(4), 1381--1394.
• Killgore, W., & Yurgelun-todd, D. (2003). Amygdala Activation During Masked Presentations of Sad and Happy Faces. Neuroimage, 19(2), e69--e70.
• Yurgelun-Todd, D. A., Killgore, W. D., & Cintron, C. B. (2003). Cognitive correlates of medial temporal lobe development across adolescence: a magnetic resonance imaging study. Perceptual and motor skills, 96(1), 3-17.
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  Adolescent development involves progressive changes in brain structure and cognitive function, but relatively few studies have documented the cognitive correlates of differences in structural brain volumes in this age group. We examined the relations among age, cognitive processing, and mesial temporal lobe volume in 37 children and adolescents. Participants completed a brief cognitive assessment battery and underwent volumetric structural magnetic resonance imaging. For the sample as a whole, amygdala volume correlated positively with age, and larger volumes of both the left and right amygdala were significantly associated with better performance on several cognitive tasks assessing academic skills and acquired knowledge in long-term memory. In contrast, hippocampal volumes did not correlate with adolescents' age and were less frequently correlated with cognitive performance. Amygdala volumes were most predictive of cognitive abilities in boys, whereas for girls, the volume of the hippocampus contributed more frequently to the prediction of cognitive abilities. These data suggest that measurable differences in mesial temporal volumes during adolescence are reliably associated with long-term cognitive abilities, particularly academic skills and the acquisition of intellectual knowledge, and that these relationships may differ as a function of the sex of the child.
• Yurgelun-Todd, D., Killgore, W., & Cintron, C. B. (2003). Cognitive correlates of medial temporal lobe development across adolescence: A magnetic resonance imaging study. PERCEPTUAL AND MOTOR SKILLS, 96(1), 3-17.
• Casasanto, D. J., Killgore, W. D., Maldjian, J. A., Glosser, G., Alsop, D. C., Cooke, A. M., Grossman, M., & Detre, J. A. (2002). Neural correlates of successful and unsuccessful verbal memory encoding. Brain and language, 80(3), 287-95.
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  Recent neuroimaging studies suggest that episodic memory encoding involves a network of neocortical structures which may act interdependently with medial temporal lobe (mTL) structures to promote the formation of durable memories, and that activation in certain structures is modulated according to task performance. Functional magnetic resonance imaging (fMRI) was used to determine the neural structures recruited during a verbal episodic encoding task and to examine the relationship between activation during encoding and subsequent recognition memory performance across subjects. Our results show performance-correlated activation during encoding both in neocortical and medial temporal structures. Neocortical activations associated with later successful and unsuccessful recognition memory were found to differ not only in magnitude, but also in hemispheric laterality. These performance-related hemispheric effects, which have not been previously reported, may correspond to between-subject differences in encoding strategy.
• Casasanto, D. J., Killgore, W., Maldjian, J. A., Glosser, G., Alsop, D. C., Cooke, A. M., Grossman, M., & Detre, J. A. (2002). Neural correlates of successful and unsuccessful verbal memory encoding. BRAIN AND LANGUAGE, 80(3), 287-295.
• Killgore, W. D. (2002). Laterality of lesions and trait-anxiety on working memory performance. Perceptual and motor skills, 94(2), 551-8.
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  An asymmetry of anterior cerebral activation favoring the right hemisphere has been associated with dispositional negative affect including trait-anxiety, while the opposite appears true of cerebral asymmetry favoring the left hemisphere. It was hypothesized that an asymmetry of cerebral activation, as defined by scores on a measure of trait-anxiety, ipsilateral to the side of an anterior brain lesion would be associated with less efficient cognitive processing than greater activation in the hemisphere contralateral to the lesion. Patients with anterior left (n = 16) or right (n = 15) hemisphere lesions completed the State-Trait Anxiety Inventory and several neurocognitive tasks. Of the abilities tested, only Digit Span scores showed an interaction between side of lesion and presumed activation asymmetry. Patients with right- but not with left-hemisphere damage showed significant differences in working memory performance depending on the presumed direction of asymmetry of the two hemispheres, supporting the dual roles of the right hemisphere in affective processing and directed attention.
• Killgore, W. D., & Cupp, D. W. (2002). Mood and sex of participant in perception of happy faces. Perceptual and motor skills, 95(1), 279-88.
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  The influences of mood-state and sex of subject were examined for ratings of the emotional intensity of videotaped facial expressions of happiness. 102 subjects who were classified by sex and their scores on the Beck Depression Inventory provided ratings of the faces. A significant sex by mood-state interaction indicated that ratings of intensity by men and women were influenced differently by mood-state, and these findings are interpreted within the framework of the Affect Infusion Model. The results support our hypothesis that men and women tend to rely preferentially on low and high affect infusion strategies, respectively. The findings further suggest that the cognitive effect of affect infusion on the magnitude of perceived intensity of facial affect could be influenced by mood-state via differences in cognitive effort subjects employ when in a dysphoric or nondysphoric mood.
• Yurgelun-Todd, D. A., Killgore, W. D., & Young, A. D. (2002). Sex differences in cerebral tissue volume and cognitive performance during adolescence. Psychological reports, 91(3 Pt 1), 743-57.
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  Adolescent development is associated with progressive increases in the ratio of cerebral white-to-gray matter volume, but it is unclear how these changes relate to cognitive development and whether they are associated with sex-specific variability in cerebral maturation. We examined sex differences in the relation between cerebral tissue volume and cognitive performance in 30 healthy adolescents (ages 13 to 17 years using morphometric magnetic resonance imaging (MRI). In the 10 boys, greater white matter volume during adolescence was positively correlated with faster speed of information processing and better verbal abilities, while cerebrospinal fluid volume was negatively correlated with verbal abilities. No significant relations between cerebral tissue volume and cognitive abilities were found for the sample of 20 girls, raising the possibility of a different developmental trajectory for females that was not sampled in the age range of this study. Findings suggest sex-specific developmental differences in the relations between cerebral structure and function.
• Killgore, W. D., & Yurgelun-Todd, D. A. (2001). Sex differences in amygdala activation during the perception of facial affect. Neuroreport, 12(11), 2543-7.
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  The cognitive and affective systems of the cerebral cortex are often more lateralized in males than females, but it is unclear whether these differences extend to subcortical systems. We used fMRI to examine sex differences in lateralized amygdala activity during happy and fearful face perception. Amygdala activation differed for men and women depending on the valence of the expression. Overall, males were more lateralized than females, but the direction differed between valence conditions. Happy faces produced greater right than left amygdala activation for males but not females. Both sexes showed greater left amygdala activation for fearful faces. These findings suggest that the lateralization of affective function may extend beyond the cortex to subcortical regions such as the amygdala.
• Killgore, W. D., Oki, M., & Yurgelun-Todd, D. A. (2001). Sex-specific developmental changes in amygdala responses to affective faces. Neuroreport, 12(2), 427-33.
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  It is hypothesized that adolescent development involves a redistribution of cerebral functions from lower subcortical structures to higher regions of the prefrontal cortex to provide greater self-control over emotional behavior. We further hypothesized that this redistribution is likely to be moderated by sex-specific hormonal changes. To examine developmental sex differences in affective processing, 19 children and adolescents underwent fMRI while viewing photographs of faces expressing fear. Males and females differed in the pattern of their amygdala vs prefrontal activation during adolescent maturation. With age, females showed a progressive increase in prefrontal relative to amygdala activation in the left hemisphere, whereas males failed to show a significant age related difference. There appear to be sex differences in the functional maturation of affect-related prefrontal-amygdala circuits during adolescence.
• Killgore, W., & Yurgelun-Todd, D. (2001). Sex differences in amygdala activation during the perception of facial affect. NEUROREPORT, 12(11), 2543-2547.
• Killgore, W., Oki, M., & Yurgelun-Todd, D. (2001). Sex-specific developmental changes in amygdala responses to affective faces. NEUROREPORT, 12(2), 427-433.
• Maldjian, J. A., Detre, J. A., Killgore, W. D., Judy, K., Alsop, D., Grossman, M., & Glosser, G. (2001). Neuropsychologic performance after resection of an activation cluster involved in cognitive memory function. AJR. American journal of roentgenology, 176(2), 541-4.
• Rohan, M., Killgore, W., Eskesen, J., Renshaw, P., & Yurgelun-Todd, D. (2001). Match-warped EPI anatomic images and the amygdala: imaging in hard places. Proc Intl Soc Mag Reson, 9, 1237.
• Casasanto, D. J., Killgore, W. D., Glosser, G., Maldjian, J. A., & Detre, J. A. (2000). Hemispheric specialization during episodic memory encoding in the human hippocampus and MTL. 6FLHQFH 6RFLHW$\backslash$.
• Casasanto, D. J., Killgore, W. D., Maldjian, J. A., Glosser, G., Grossman, M., Alsop, D. C., & Detre, J. A. (2000). Neural correlates of successful and unsuccessful verbal encoding. NeuroImage, 11(5), S381.
• Killgore, W. D. (2000). Academic and research interest in several approaches to psychotherapy: a computerized search of literature in the past 16 years. Psychological reports, 87(3 Pt 1), 717-20.
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  A computerized search of published abstracts in PsychInfo was conducted to obtain the frequency of annual citations since 1984 for six forms of psychotherapy. Cognitive-Behavioral therapies showed the most rapid increase over the past 16 years. Family therapies, in contrast, showed a significant decline in the number of abstract citations since 1990. At present, brief, empirically tested treatments appear to be generating the greatest discussion in the academic and scientific literature.
• Killgore, W. D. (2000). Academic and research interest in several approaches to psychotherapy: a computerized search of literature in the past 16 years. Psychological reports, 87(3), 717--720.
• Killgore, W. D. (2000). Evidence for a third factor on the Positive and Negative Affect Schedule in a college student sample. Perceptual and Motor Skills, 90, 147--152.
• Killgore, W. D. (2000). Evidence for a third factor on the Positive and Negative Affect Schedule in a college student sample. Perceptual and motor skills, 90(1), 147-52.
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  The Positive and Negative Affect Schedule (PANAS) was originally developed to measure two orthogonal dimensions of affect. The present study examined the factor structure of the PANAS in a sample of 302 undergraduates. maximum Likelihood factor analysis was used to compare two- and three-factor solutions to self-rated affect. The two-factor solution resulted in confirmation of the two factors of Positive and Negative Affect hypothesized to underlie the schedule. When, however, a three-factor solution was specified, the Positive Affect factor was retained, while the Negative Affect factor split into two lower-order factors generally consistent with the Upset and Afraid factors described by Mehrabian in 1997. These findings highlight the need for research to consider the possible influence of a third affective dimension, such as Dominance-Submissiveness on self-rated affective experience.
• Killgore, W. D. (2000). Sex differences in identifying the facial affect of normal and mirror-reversed faces. Perceptual and motor skills, 91(2), 525-30.
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  The influences of sex and lateralized visual hemispace bias in the judgment of the emotional valence of faces during a free viewing condition are evaluated. 73 subjects (aged 18 to 52 yr.) viewed videotaped facial expressions of emotion in normal and mirror-reversed orientation and classified each face as a positive, negative, or neutral expression. There was a significant interaction between the sex of the rater and the orientation of the face that influenced the proportion of correct classifications. Male and female perceivers did not differ in the accuracy of their affect judgments for faces viewed in normal orientation, whereas reversal of the orientation of the faces resulted in a significant enhancement of accuracy judgments for the males but not the females. The results suggest greater cerebral lateralization of perceptual processes in males.
• Killgore, W. D. (2000). Sex differences in identifying the facial affect of normal and mirror-reversed faces. Perceptual and motor skills, 91, 525--530.
• Killgore, W. D., & DellaPietra, L. (2000). Using the WMS-III to detect malingering: empirical validation of the rarely missed index (RMI). Journal of clinical and experimental neuropsychology, 22(6), 761-71.
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  To detect malingering during memory assessment, we evaluated item response biases to the Logical Memory Delayed Recognition (LMDR) subtest of the WMS-III. In a sample of 50 healthy volunteers who were completely naïve to the content of the Logical Memory stories, 6 LMDR items were correctly endorsed above chance probabilities. These 6 rarely missed items significantly discriminated 51 patients with neurological impairment from 36 volunteers who attempted to feign head injury and poor cognitive performance. A weighted combination of the 6 items was summed to form a single Rarely Missed Index (RMI). The RMI accurately classified over 98% of participants and demonstrated high sensitivity (97%) and specificity (100%) in discriminating between analog malingerers and patients. Because the RMI is calculated directly from the LMDR items, it has the advantage of requiring no additional administration time or materials, and thus may serve as a quick screen for dissimulation that can be obtained without additional testing.
• Killgore, W. D., & Dellapietra, L. (2000). Item Response Biases on the Logical Memory Delayed Recognition Subtest of the Wechsler Memory Scale—III. Psychological reports, 86(3), 851--857.
• Killgore, W. D., & Dellapietra, L. (2000). Item response biases on the logical memory delayed recognition subtest of the Wechsler Memory Scale-III. Psychological reports, 86(3 Pt 1), 851-7.
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  We hypothesized that the wording and sequential order of the WMS-III Logical Memory recognition questions may bias subjects toward correct or incorrect responses on specific items. Therefore, we classified each item according to one of three potential sources of bias (yeasaying to proper names, priming of "yes" responses by previous items with similar content, naysaying to unlikely occurrences) and administered the items to 31 subjects who were completely naïve to the story content. The items predicted to have correct endorsement biases were answered correctly at greater than chance frequencies, while items predicted to be biased toward incorrect answers were missed more frequently than expected by chance. The same sources of bias were tested in an independent clinical sample of 36 neurological patients who were administered the WMS-III in the standard manner. In these patients biases appeared robust enough to be detected in the performances of clinical patients during a neuropsychological evaluation. With further research, such biases may provide avenues for detecting malingering.
• Killgore, W. D., Casasanto, D. J., Yurgelun-Todd, D. A., Maldjian, J. A., & Detre, J. A. (2000). Functional activation of the left amygdala and hippocampus during associative encoding. Neuroreport, 11(10), 2259-63.
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  The human hippocampus is critical to episodic encoding, but the role of the amygdala in memory is less clear. Animal research suggests a role for the amygdala in associative memory, but this has not been examined systematically in humans. Using fMRI, we compared amygdala and hippocampus activation for seven healthy subjects during two visual encoding tasks: serially presented single faces and faces presented as pairs. Single faces activated bilateral hippocampi, but not the amygdala. Paired faces activated bilateral amygdala, but only the left hippocampus. Subtraction of the two conditions revealed greater activation within the left amygdala and hippocampus during paired face encoding, suggesting that associative encoding activates a left-lateralized limbic network including the hippocampus and amygdala.
• Killgore, W., & DellaPietra, L. (2000). Using the WMS-III to detect malingering: Empirical validation of the Rarely Missed Index (RMI). JOURNAL OF CLINICAL AND EXPERIMENTAL NEUROPSYCHOLOGY, 22(6), 761-771.
• Oki, M., Gruber, S. A., Killgore, W. D., & Yurgelun-Todd, D. A. (2000). Bilateral thalamic activation occurs during lexical but not semantic processing. NeuroImage, 11(5), S353.
• Yurgelun-Todd, D. A., Gruber, S. A., Kanayama, G., Killgore, W. D., Baird, A. A., & Young, A. D. (2000). fMRI during affect discrimination in bipolar affective disorder. Bipolar disorders, 2(3 Pt 2), 237-48.
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  It has been hypothesized that disturbances in affect may represent distinct etiologic factors for bipolar affective disorder. The neural mechanisms mediating affective processes and their relationship to brain development and the pathophysiology of bipolar affective disorder remain to be clarified. Recent advances in neuroimaging techniques have made possible the non-invasive examination of specific brain regions during cortical challenge paradigms. This study reports findings based on fMRI data acquired during fearful and happy affect recognition paradigms in patients with bipolar affective disorder and in healthy adult subjects.
• Yurgelun-Todd, D., Gruber, S. A., Kanayama, G., Killgore, W., Baird, A. A., & Young, A. D. (2000). fMRI during affect discrimination in bipolar affective disorder. BIPOLAR DISORDERS, 2(3), 237-248.
• Killgore, W. D. (1999). Affective valence and arousal in self-rated depression and anxiety. Perceptual and motor skills, 89(1), 301-4.
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  To evaluate the predictive utility of Russell's two-dimensional model of affect to the experience of depression and anxiety, self-report ratings of pleasure and arousal were obtained from 200 undergraduates using the Affect Grid. Ratings of Pleasure and Arousal each accounted for significant variance in predicting depression scores on the Beck Depression Inventory and Profile of Mood States. Only ratings of Pleasure, however, were predictive of Anxiety scores on the Profile of Mood States, whereas the relationship between Arousal ratings and Anxiety scores was more complex, demonstrating possible moderation by variables consistent with a third dimension of Dominance-Submissiveness, as postulated by other investigators.
• Killgore, W. D. (1999). Empirically derived factor indices for the Beck Depression Inventory. Psychological reports, 84(3 Pt 1), 1005-13.
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  Factor analytic studies of the Beck Depression Inventory routinely yield a small number of factors that parsimoniously summarize the 21 items of the inventory. To improve the utility of such factor data within clinical or applied research settings, the present study aimed to develop a set of empirically derived depression indices based on the factor structure of the Beck Depression Inventory. In Study 1, principal-axis factor analysis of the responses of 303 undergraduate students yielded a 2-factor solution that accounted for 33% of the common variance. Easily calculated factor indices were developed to reflect individual performance on each factor, and normative data from the sample were used to establish preliminary guidelines for evaluating severity on each index. In Study 2, analyses of the factor-index scores obtained from a clinical sample of 55 medical patients supported the utility of the index scores for discriminating among various aspects of dysphoric experience.
• Killgore, W. D. (1999). Empirically derived factor indices for the Beck Depression Inventory. Psychological reports, 84(3), 1005--1013.
• Killgore, W. D. (1999). The visual analogue mood scale: can a single-item scale accurately classify depressive mood state?. Psychological reports, 85(3 Pt 2), 1238-43.
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  Visual analogue mood scales provide extremely rapid, single-item assessment of affective states. This study examined discrimination on a single-item visual analogue depression scale between dysphoric or mildly depressed and nondepressed individuals in a sample of 284 college students. The visual analogue mood scale significantly discriminated subjects by mood category and achieved comparable hit rate, sensitivity, and specificity relative to other well validated mood scales.
• Killgore, W. D. (1999). The visual analogue mood scale: can a single-item scale accurately classify depressive mood state?. Psychological reports, 85(3 suppl), 1238--1243.
• Killgore, W. D., & Adams, R. L. (1999). Prediction of Boston Naming Test performance from vocabulary scores: preliminary guidelines for interpretation. Perceptual and motor skills, 89(1), 327-37.
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  Patients with limited education or underdeveloped vocabulary skills may perform below the normal range on the Boston Naming Test when compared to the original published norms, even in the absence of brain damage. To reduce the frequency of false positive dysnomic classifications of patients with limited vocabulary skills, we developed a score adjustment to account for the significant shared variance between scores on this test and the WAIS-R Vocabulary subtest. Vocabulary significantly predicted performance on the Boston Naming Test (r = .65, p < .0001) in a sample of 62 outpatients who had no objective evidence of brain damage. Linear regression was used to derive expected performance on the Boston Naming Test from Vocabulary scaled scores. Relative to the original published norms, scores based on the Vocabulary subtest cut-offs produced fewer false positives and more accurately classified group membership for patients with and without objectively verified brain damage. These performance predictions are offered as tentative guidelines to assist clinicians in evaluating the presence of naming deficits by controlling for the variance associated with knowledge of vocabulary.
• Killgore, W. D., & Gangestad, S. W. (1999). Sex differences in asymmetrically perceiving the intensity of facial expressions. Perceptual and motor skills, 89(1), 311-4.
  More info

  Emotional facial expressions are often asymmetrical, with the left half of the face typically displaying the stronger affective intensity cues. During facial perception, however, most right-handed individuals are biased toward facial affect cues projecting to their own left visual hemifield. Consequently, mirror-reversed faces are typically rated as more emotionally intense than when presented normally. Mirror-reversal permits the most intense side of the expresser's face to project to the visual hemifield biased for processing facial affect cues. This study replicated the mirror-reversal effect in 21 men and 49 women (aged 18-52 yr.) using a videotaped free viewing presentation but also showed the effect of facial orientation is moderated by the sex of the perceiver. The mirror-reversal effect was significant only for men but not for women, suggesting possible sex differences in cerebral organization of systems for facial perception.
• Killgore, W. D., DellaPietra, L., & Casasanto, D. J. (1999). Hemispheric laterality and self-rated personality traits. Perceptual and motor skills, 89(3 Pt 1), 994-6.
  More info

  Cerebral hemispheric lateralization and personality traits were evaluated in 154 undergraduate and nonclinical volunteers. Personality ratings did not differ significantly between groups defined on the basis of hand, eye, or ear preference.
• Killgore, W. D., Glosser, G., Casasanto, D. J., French, J. A., Alsop, D. C., & Detre, J. A. (1999). Functional MRI and the Wada test provide complementary information for predicting post-operative seizure control. Seizure, 8(8), 450-5.
  More info

  Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone.
• Killgore, W., & Dellapietra, L. (1999). Item response biases on the WMS-III auditory delayed recognition subtests. Archives of Clinical Neuropsychology, 14(1), 92--92.
• Killgore, W., Glosser, G., & Detre, J. (1999). Prediction of seizure outcome following anterior temporal lobectomy: fMRI vs. IAT. Archives of Clinical Neuropsychology, 14(1), 143--143.
• Killgore, W., Glosser, G., Casasanto, D. J., French, J. A., Alsop, D. C., & Detre, J. A. (1999). Functional MRI and the Wada test provide complementary information for predicting post-operative seizure control. SEIZURE-EUROPEAN JOURNAL OF EPILEPSY, 8(8), 450-455.
• KlLLGOHE, W. D. (1999). AFFECTIVE VALENCE AND AROUSAL IN SELF-RATED DEPRESSION AND ANXIETY’. Perceptual and motor skills, 89, 301--304.
• Killgore, W. D. (1998). The Affect Grid: a moderately valid, nonspecific measure of pleasure and arousal. Psychological reports, 83(2), 639-42.
  More info

  The Affect Grid was first published in 1989 as a single-item measure of the two affect dimensions of pleasure-displeasure and arousal-sleepiness; however, over the past decade no subsequent validation studies have been published and no further mention of this potentially useful measure has appeared in the literature. In this study, scores on the Affect Grid were obtained from 284 college students and correlated with scores on the Beck Depression Inventory, Positive and Negative Affect Schedule, and the Profile of Mood States. Factor analytic and correlational findings suggest that the Affect Grid is a moderately valid measure of the general dimensions of pleasure and arousal but has little specificity in discriminating among various qualities of affective experience.
• Killgore, W., & Adams, R. (1998). Vocabulary ability and Boston naming test performance: Interpretive guidelines. Archives of Clinical Neuropsychology, 13(1), 31.
• Killgore, W., Glosser, G., Alsop, D., Cooke, A., McSorley, C., Grossman, M., & Detre, J. (1998). Functional activation during material specific memory encoding. NeuroImage, 7(4 PART II).

Proceedings Publications

• Alkozei, A., Grandner, M., & Killgore, W. (2016, June). Exposure to blue wavelength light is associated with increased dorsolateral prefrontal cortex responses, and increases in response times during a working memory task.. In SLEEP.
• Alkozei, A., Grandner, M., & Killgore, W. (2016, June). Exposure to blue wavelength light reduces activation within the anterior cingulate cortex during anticipation of certain reward stimuli.. In SLEEP.
• Davis, B., Yang, R., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Nightmares in a community sample: Prevalence and associations with daytime function independent of poor sleep quality and depression. In SLEEP.
• Fisseha, E., Havens, C., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Sleep duration’s important role in the relationship among difficulty concentrating, fatigue, stress, and depressed mood: Data from the SHADES study. In SLEEP.
• Graham, P. M., Goldstein, M., David, B. M., Perlis, M. L., Perfect, M. M., Frye, S., Killgore, W., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Longitudinal analysis of sleep duration using actigraphy and sleep diary: Stability and agreement over 8-11 months. In SLEEP.
• Granados, K., Rojo-Wissar, D. M., Chakravorty, S., Prather, A., Perfect, M. M., Frye, S., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Adverse childhood exposures associated with adult insomnia symptoms. In SLEEP.
• Grandner, M., & Killgore, W. (2016, June). Positive and negative mood ratings across 24 hours. In SLEEP.
• Jackson, N., Patterson, F., Seixas, A., Jean-Louis, G., Killgore, W., & Grandner, M. (2016, June). Using big data to determine social, behavioral, and environmental determinants of sleep duration in the US population: Application of a machine-learning approach to data from approximately 700,000 Americans. In SLEEP.
• Killgore, W., Tkachenko, O., Grandner, M., & Rauch, S. L. (2016, June). Default mode activation predicts vulnerability to sleep deprivation in the domains of mood, sleepiness, and vigilance. In SLEEP.
• Killgore, W., Weber, M., Grandner, M., & Penetar, D. M. (2016, June). Blue wavelength light therapy improves balance following mild traumatic brain injury. In SLEEP.
• Kotzin, M. D., Alkozei, A., Grandner, M., & Killgore, W. (2016, June). The effects of trait gratitude on quality of sleep, intrusiveness of pre-sleep cognitions, and daytime energy in healthy individuals. In SLEEP.
• Markowski, S. M., Alkozei, A., McIntosh, M. B., Grandner, M., & Killgore, W. (2016, June). Chronotype and risk-taking propensity. In SLEEP.
• McIntosh, M. B., Markowski, S. M., Grandner, M., & Killgore, W. (2016, June). Short-term sleep duration is negatively associated with impulsivity in women. In SLEEP.
• Meridew, C. M., Jaszewski, A., Newman-Smith, K., Killgore, W., Gallagher, R., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Sleep practices, beliefs, and attitudes associated with overall health. In SLEEP.
• Ocano, D., Jean-Louis, G., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Sleep duration and decreased social support from family, friends, and significant other: Influence of insomnia and perceived stress level. In SLEEP.
• Okuagu, A., Perlis, M. L., Ellis, J. A., Prather, A. A., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Does thinking keep people awake? Or does it matter what they are thinking about? Self-directed cognitions associated with insomnia and insufficient sleep. In SLEEP.
• Olivier, K., Gallagher, R. A., Killgore, W., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Development and initial validation of the assessment of sleep environment: A novel inventory for describing and quantifying the impact of environmental factors on sleep. In SLEEP.
• Paine, K. N., Forbush, S., Ellis, J. A., Nowakowski, S., Newman-Smith, K., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Sleep duration and satisfaction with life, health, finances, and relationship. In SLEEP.
• Rhee, J. U., Haynes, P. L., Chakravorty, S., Patterson, F., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Susceptibility to smoking during the day and its relationship with insomnia and sleep duration. In SLEEP.
• Roberts, S. E., Singh, P., Grandner, M., & Killgore, W. (2016, June). Later wake up time and impulsivity. In SLEEP.
• Saccone, J., Davis, B., Chakravorty, S., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Habitual caffeine use and motivation to consume caffeine: Associations with sleep duration, sleepiness, fatigue, and insomnia severity. In SLEEP.
• Singh, A., Fridman, A., Silveri, M. M., Grandner, M., & Killgore, W. (2016, June). Medial prefrontal GABA predicts hunger ratings during sleep deprivation for men but not women. In SLEEP.
• Vanuk, J. R., Alkozei, A., Grandner, M., & Killgore, W. (2016, June). The effects of light exposure on heart rate variability predict sleepiness and vigilance. In SLEEP.
• Vanuk, J. R., Alkozei, A., Smith, R., Grandner, M., & Killgore, W. (2016, June). Changes in heart rate variability due to light exposure predict frontoparietal connectivity. In SLEEP.
• Warlick, C., Chakravorty, S., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Timing of alcohol intake associated with insomnia symptoms. In SLEEP.
• Waugaman, D. L., Markowski, S. M., Alkozei, A., Grandner, M., & Killgore, W. (2016, June). Chronotype and emotional intelligence. In SLEEP.
• Weber, M., Grandner, M., & Killgore, W. (2016, June). Blue wavelength light therapy reduces daytime sleepiness following mild traumatic brain injury. In SLEEP.
• Weber, M., Grandner, M., & Killgore, W. (2016, June). Grey matter correlates of daytime sleepiness.. In SLEEP.
• Yang, R., Ocano, D., Chakravorty, S., Killgore, W., Gallagher, R. A., Carrazco, N., Alfonso-Miller, P., Gehrels, J., & Grandner, M. (2016, June). Relationship between insomnia and depression moderated by caffeine.. In SLEEP.
• Alkozei, A., Pisner, D., Rauch, S. L., & Killgore, W. D. (2015). Emotional Intelligence and Subliminal Presentations of Social Threat. In BIOLOGICAL PSYCHIATRY, 77.
• Buchholz, J. L., Rosso, I. M., Killgore, W. D., Fukunaga, R., Olson, E. A., Demers, L. A., & Rauch, S. L. (2015). Amygdala Volume Is Associated with Helplessness in Adults with Major Depressive Disorder (MDD). In BIOLOGICAL PSYCHIATRY, 77.
• Killgore, W. D., Rosso, I. M., Rauch, S. L., & Nickerson, L. D. (2015). Emotional Intelligence Correlates with Coordinated Resting State Activity Between Brain Networks involved in Emotion Regulation and Interoceptive Experience. In BIOLOGICAL PSYCHIATRY, 77.
• Killgore, W. D., Tkachenko, O., Gogel, H., Kipman, M., Sonis, L. A., Weber, M., Divatia, S. C., Demers, L. A., Olson, E. A., Buchholz, J. L., & others, . (2015). Activation of the Ventral Striatum Predicts Overeating During Subsequent Loss of Sleep. In BIOLOGICAL PSYCHIATRY, 77.
• Killgore, W. D., Vanuk, J. R., Alkozei, A., Markowski, S. M., Pisner, D., Shane, B., Fridman, A., & Knight, S. A. (2015). Daytime Sleepiness Is Associated with Altered Thalamocortical Connectivity. In BIOLOGICAL PSYCHIATRY, 77.
• Pisner, D., Alkozei, A., & Killgore, W. D. (2015). Trait Emotional Suppression Is Associated with Decreased Activation of the Insula and Thalamus in response to Masked Angry Faces. In BIOLOGICAL PSYCHIATRY, 77.
• Rosso, I., Olson, E., Killgore, W. D., Fukunaga, R., Webb, C., & Rauch, S. (2015). A Randomized Trial of Internet-Based Cognitive Behavioral Therapy for Major Depressive Disorder. In NEUROPSYCHOPHARMACOLOGY, 40.
• Shane, B. R., Alkozei, A., Vanuk, J. R., Weber, M., & Killgore, W. D. (2015). The Effect of Bright Light Therapy for Improving Sleep Among Individuals with Mild Traumatic Brain Injury. In BIOLOGICAL PSYCHIATRY, 77.
• Sneider, J. T., Killgore, W. D., Rauch, S. L., Jensen, J. E., & Silveri, M. M. (2015). Sex Differences in the Associations Between Prefrontal GABA and Resistance to Sleep Deprivation. In BIOLOGICAL PSYCHIATRY, 77.
• Vanuk, J. R., Fridman, A., Demers, L., & Killgore, W. D. (2015). Engaging in Meditation and Internet-Based Training as a Means of Enhancing Emotional Intelligence. In BIOLOGICAL PSYCHIATRY, 77.
• Vanuk, J. R., Shane, B. R., Alkozei, A., & Killgore, W. D. (2015). Trait Emotional Intelligence Is Associated with Greater Resting State Functional Connectivity within the Default Mode and Task Positive Networks. In BIOLOGICAL PSYCHIATRY, 77.
• Brennan, B., Tkachenko, O., Schwab, Z., Ryan, E., Athey, A., Pope, H., Dougherty, D., Jenike, M., Killgore, W., Hudson, J., & others, . (2014). An Examination of Rostral Anterior Cingulate Cortex Function and Neurochemistry in Obsessive-compulsive Disorder. In NEUROPSYCHOPHARMACOLOGY, 39.
• Demers, L. A., Preer, L. A., Gogel, H., Olson, E. A., Weber, M., & Killgore, W. D. (2014). Left-hemifield bias on sad chimeric face task correlates with interpersonal emotional intelligence. In BIOLOGICAL PSYCHIATRY, 75.
• Killgore, W. (2014). Sleep Deprivation and Behavioral Risk-Taking. In Elsevier Inc..
• Killgore, W. D., Weber, M., Olson, E. A., & Rauch, S. L. (2014). Sleep reduction and functioning of the emotion regulation circuitry. In BIOLOGICAL PSYCHIATRY, 75.
• Killgore, W., Demers, L., Olson, E., Rosso, I., Webb, C., & Rauch, S. (2014). Anterior Cingulate Gyrus and Sulcus Thickness: A Potential Predictor of Remission following Internet-Based Cognitive Behavioral Therapy for Major Depressive Disorder. In NEUROPSYCHOPHARMACOLOGY, 39.
• Rauch, S., Olson, E., Buchholz, J., Rosso, I., Killgore, W., Webb, C., & Gogel, H. (2014). Internet-based Cognitive Behavioral Therapy Effects on Symptom Severity in Major Depressive Disorder: Preliminary Results from a Randomized Controlled Trial. In NEUROPSYCHOPHARMACOLOGY, 39.
• Weber, M., Penetar, D. M., Trksak, G. H., Kipman, M., Tkachenko, O., Bark, J. S., Jorgensen, A. L., Rauch, S. L., & Killgore, W. D. (2014). Light therapy may improve sleep and facilitate recovery from mild traumatic brain injury. In Abstract presented at the 10 th World Congress on Brain Injury, San Francisco, CA.
• Brennan, B. P., Schwab, Z. J., Athey, A. J., Ryan, E. M., Killgore, W. D., Jenike, M. A., & Rauch, S. L. (2013). A Functional Magnetic Resonance Imaging Study of Rostral Anterior Cingulate Cortex Activation in Obsessive-Compulsive Disorder Using an Emotional Counting Stroop Paradigm. In BIOLOGICAL PSYCHIATRY, 73.
• Killgore, W. (2013). Sleep Duration Contributes to Cortico-Limbic Functional Connectivity, Emotional Functioning, \& Psychological Health. In NEUROPSYCHOPHARMACOLOGY, 38.
• Killgore, W. D., Schwab, Z. J., Kipman, M., DelDonno, S., Rauch, S. L., & Weber, M. (2013). Problems with sleep initiation and sleep maintenance correlate with functional connectivity among primary sensory cortices. In BIOLOGICAL PSYCHIATRY, 73.
• Kipman, M., Schwab, Z. J., DelDonno, S., Weber, M., Rauch, S. L., & Killgore, W. D. (2013). The neurocircuitry of impulsive behavior. In BIOLOGICAL PSYCHIATRY, 73.
• Preer, L. A., Tkachenko, O., Gogel, H., Schwab, Z. J., Kipman, M., DelDonno, S., Weber, M., Webb, C. A., Rauch, S. L., & Killgore, W. D. (2013). Linking Sleep Trouble to Neuroticism, Emotional Control, and Impulsiveness. In BIOLOGICAL PSYCHIATRY, 73.
• Webb, C. A., Killgore, W. D., Britton, J. C., Schwab, Z. J., Price, L. M., Weiner, M. R., Gold, A. L., Rosso, I. M., Simon, N. M., Pollack, M. H., & others, . (2013). Comparing Categorical versus Dimensional Predictors of Functional Response Across Three Anxiety Disorders. In BIOLOGICAL PSYCHIATRY, 73.
• Weber, M., Killgore, W. D., Rosso, I. M., Britton, J. C., Simon, N. M., Pollack, M. H., & Rauch, S. L. (2013). Gray Matter Correlates of Posttraumatic Stress Disorder-A Voxel-Based Morphometry Study. In BIOLOGICAL PSYCHIATRY, 73.
• Weber, M., Penetar, D. M., Trksak, G. H., DelDonno, S. R., Kipman, M., Schwab, Z. J., Rauch, S. L., & Killgore, W. D. (2013). Morning blue wavelength light therapy improves sleep, cognition, emotion and brain function following mild traumatic brain injury. In BIOLOGICAL PSYCHIATRY, 73.
• Killgore, W. (2012). Socio-emotional and neurocognitive effects of sleep loss. In Ashgate Publishing Ltd.
• Killgore, W. D., Britton, J. C., Rosso, I. M., Schwab, Z. J., & Rauch, S. L. (2012). Shared and unique patterns of cortico-limbic activation across anxiety disorders. In BIOLOGICAL PSYCHIATRY, 71.
• Killgore, W. D., Schwab, Z. J., & Rauch, S. L. (2012). Daytime sleepiness affects prefrontal inhibition of food consumption. In BIOLOGICAL PSYCHIATRY, 71.
• Killgore, W., Schwab, Z., DelDonno, S., Kipman, M., Weber, M., & Rauch, S. (2012). Greater nocturnal sleep time is associated with increased default mode functional connectivity. In SLEEP, 35.
• Kipman, M., Schwab, Z., Weber, M., DelDonno, S., & Killgore, W. (2012). Yawning frequency is correlated with reduced medial thalamic volume. In SLEEP, 35.
• Kipman, M., Weber, M., DelDonno, S., Schwab, Z., & Killgore, W. (2012). Morningness-Eveningness correlates with orbitofrontal gray matter volume. In SLEEP, 35.
• Schwab, Z., & Killgore, W. (2012). Daytime sleepiness affects prefrontal regulation of food intake. In SLEEP, 35.
• Sneider, J., Killgore, W., Schwab, Z., Crowley, D., Covell, M., Cohen-Gilbert, J., & Silveri, M. (2012). INHIBITORY CAPACITY IN EMERGING ADULT BINGE DRINKERS: INFLUENCE OF FACIAL CUES. In ALCOHOLISM-CLINICAL AND EXPERIMENTAL RESEARCH, 36.
• Weber, M., DelDonno, S., Kipman, M., Schwab, Z., & Killgore, W. (2012). GRAY MATTER CORRELATES OF SELF-REPORTED SLEEP DURATION. In SLEEP, 35.
• Killgore, W. (2011). Caffeine and other alerting agents. In Cambridge University Press.
• Killgore, W. D., Rosso, I. M., Britton, J. C., Schwab, Z. J., Weiner, M. R., & Rauch, S. L. (2011). Cortico-limbic activation differentiates among anxiety disorders with and without a generalized threat response. In BIOLOGICAL PSYCHIATRY, 69.
• Killgore, W., & Balkin, T. (2011). DOES VULNERABILITY TO SLEEP DEPRIVATION INFLUENCE THE EFFECTIVENESS OF STIMULANTS ON PSYCHOMOTOR VIGILANCE?. In SLEEP, 34.
• Killgore, W., Grugle, N., & Balkin, T. (2011). Sleep deprivation impairs recognition of specific emotions. In Sleep, 34.
• Schwab, Z. J., Weiner, M. R., Rauch, S. L., & Killgore, W. D. (2011). Emotional and cognitive intelligence: Support for the neural efficiency hypothesis. In BIOLOGICAL PSYCHIATRY, 69.
• Schwab, Z., Weiner, M., & Killgore, W. (2011). Functional MRI correlates of morningness-eveningness during visual presentation of high calorie foods. In Sleep, 34.
• Weiner, M. R., Schwab, Z. J., Rauch, S. L., & Killgore, W. D. (2011). Personality factors predict brain responses to images of high-calorie foods. In BIOLOGICAL PSYCHIATRY, 69.
• Weiner, M., Schwab, Z., & Killgore, W. (2011). Daytime sleepiness is associated with altered brain activation during visual perception of high-calorie foods: An fMRI study. In SLEEP, 34.
• Capaldi, V., Guerrero, M., & Killgore, W. (2010). Sleep disorders among OIF and OEF Soldiers. In SLEEP, 33.
• Killgore, D., Killgore, W., Grugle, N., & Balkin, T. (2010). SUBJECTIVE SLEEPINESS AND OBJECTIVE PERFORMANCE: DIFFERENTIAL EFFECTS OF STIMULANTS DURING SLEEP DEPRIVATION. In SLEEP, 33.
• Killgore, W. (2010). Cortical and Limbic Activation in Response to Low-and High-calorie Food. In Elsevier Inc..
• Killgore, W. D., Kamimori, G. H., & Balkin, T. J. (2010). Sleep deprivation selectively impairs emotional aspects of cognitive functioning. In Oral platform presentation at the 27 th Army Science Conference, Orlando, FL.
• Killgore, W. D., Killgore, D. B., Kamimori, G. H., & Balkin, T. J. (2010). Caffeine Reduces Behavioral Risk-Taking During Sleep Deprivation. In BIOLOGICAL PSYCHIATRY, 67.
• Killgore, W. D., Price, L. M., Britton, J. C., Simon, N. M., Pollack, M. H., Schwab, Z. J., Weiner, M. R., Rosso, I. M., & Rauch, S. L. (2010). Paralimbic responses to masked emotional faces in PTSD: Disorder and valence specificity. In BIOLOGICAL PSYCHIATRY, 67.
• Killgore, W., Conrad, T., Grugle, N., & Balkin, T. (2010). Baseline executive function abilities predict risky behavior following sleep deprivation. In SLEEP, 33.
• Killgore, W., Kamimori, G. H., & Balkin, T. J. (2010). Caffeinated gum minimizes risk-taking in soldiers during prolonged sleep deprivation. In Abstract presented at the 27 th Army Science Conference, Orlando, FL.
• Rosso, I. M., Makris, N., Britton, J. C., Price, L. M., Gold, A. L., Deckersbach, T., Killgore, W. D., & Rauch, S. L. (2010). Anxiety Sensitivity Correlates with Insular Cortex Volume and Thickness in Specific Animal Phobia. In BIOLOGICAL PSYCHIATRY, 67.
• Rupp, T., Killgore, W., & Balkin, T. (2010). VULNERABILITY TO SLEEP DEPRIVATION IS DIFFERENTIALLY MEDIATED BY SOCIAL EXPOSURE IN EXTRAVERTS VS. INTROVERTS. In SLEEP, 33.
• Yurgelun-Todd, D., & Killgore, W. (2010). FUNCTIONAL MRI CORRELATES OF SELF-REPORTED DAYTIME SLEEPINESS. In SLEEP, 33.
• Britton, J. C., Stewart, S. E., Price, L. M., Killgore, W. D., Jenike, M. A., & Rauch, S. L. (2009). The Neural Correlates of Negative Priming in Pediatric Obsessive Compulsive Disorder.. In BIOLOGICAL PSYCHIATRY, 65.
• Killgore, D., Killgore, W., Grugle, N., & Balkin, T. (2009). EXECUTIVE FUNCTIONS PREDICT THE ABILITY TO SUSTAIN PSYCHOMOTOR VIGILANCE DURING SLEEP LOSS. In SLEEP, 32.
• Killgore, W., & Yurgelun-Todd, D. (2009). Trouble falling asleep is associated with reduced activation of dorsolateral prefrontal cortex during a simple attention task. In SLEEP, 32.
• Killgore, W., Killgore, D., Kamimori, G., & Balkin, T. (2009). Caffeine protects against increased risk-taking behavior during severe sleep deprivation. In SLEEP, 32.
• Estrada, A., Killgore, W., Rouse, T., Balkin, T., & Wildzunas, R. (2008). Total sleep time measured by actigraphy predicts academic performance during military training. In Sleep, 31.
• Killgore, W., Lipizzi, E., Killgore, D., Rupp, T., Kamimori, G., & Balkin, T. (2008). Emotional intelligence predicts declines in emotion-based decision-making following sleep deprivation. In SLEEP, 31.
• Killgore, D., McBride, S., Balkin, T., Grugle, N., & Killgore, W. (2007). Changes in odor discrimination predict executive function deficits following 45 hours of wakefulness. In SLEEP, 30.
• McBride, S., Ganesan, G., Kamimori, G., & Killgore, W. (2007). Odor identification ability predicts vulnerability to attentional lapses during 77 hours of sleep deprivation. In SLEEP, 30.
• Newman, R., Krugler, A., Kamimori, G., & Killgore, W. (2007). Changes in state and trait anger following 56 hours of sleep deprivation. In SLEEP, 30.
• Newman, R., Smith, K., Balkin, T., Grugle, N., & Killgore, W. (2007). The effects of caffeine, dextroamphetamine, and modafinil on executive functioning following 45 hours of sleep deprivation. In SLEEP, 30.
• Richards, J., Lipizzi, E., Balkin, T., Grugle, N., & Killgore, W. (2007). Objective alertness correlates with mood changes during 44 hours of sleep deprivation. In SLEEP, 30.
• Richards, J., Lipizzi, E., Kamimori, G., & Killgore, W. (2007). Extroversion predicts increased attentional lapses during sleep deprivation. In Sleep, 30.
• Rupp, T., Grugle, N., Krugler, A., Balkin, T., & Killgore, W. (2007). Caffeine, dextroamphetamine, and modafinil improve PVT performance after sleep deprivation and recovery sleep. In SLEEP, 30.
• Bailey, J., Richards, J., & Killgore, W. (2006). Prediction of mood fluctuations during sleep deprivation with the SAFTE Model. In SLEEP, 29.
• Huck, N., Kendall, A., McBride, S., & Killgore, W. (2006). The perception of facial emotion is enhanced by psychostimulants following two nights of sleep deprivation. In Sleep, 29.
• Kahn-Green, E., Conrad, A., Killgore, D., Kaminiori, G., & Killgore, W. (2006). Tired and frustrated: Using a projective technique for assessing responses to stress during sleep deprivation. In SLEEP, 29.
• Kahn-Green, E., Day, L., Conrad, A., Leavitt, B., Killgore, D., & Killgore, W. (2006). Short-term vs. long-term planning abilities: differential effects of stimulants on executive function in sleep deprived individuals. In Sleep, 29.
• Kendall, A., McBride, S., Kamimori, G., & Killgore, W. (2006). The interaction of coping skills and stimulants on sustaining vigilance: Poor coping may keep you up at night. In SLEEP, 29.
• Killgore, D., Kahn-Green, E., Balkin, T., Kamimori, G., & Killgore, W. (2006). 56 hours of wakefulness is associated with a subclinical increase in symptoms of psychopathology. In SLEEP, 29.
• Killgore, W., Killgore, D., Kahn-Green, E., Conrad, A., Balkin, T., & Kamimori, G. (2006). Introversive personalities are more resilient against sleep loss. In Sleep, 29.
• Krugler, A., Killgore, W., & Kamimori, G. (2006). Trait anger predicts resistance to sleep loss. In SLEEP, 29.
• Lipizzi, E., Killgore, D., Kahn-Green, E., Kamimori, G., & Killgore, W. (2006). Emotional intelligence scores decline during sleep deprivation. In SLEEP, 29.
• Lipizzi, E., Leavitt, B., Killgore, D., Kamimori, G., & Killgore, W. (2006). Decision making capabilities decline with increasing duration of wakefulness. In Sleep, 29.
• McBride, S., Killgore, D., Balkin, T., Kamimori, G., & Killgore, W. (2006). Sleepy people smell worse: Olfactory decrements as a function of sleep deprivation. In SLEEP, 29.
• McBride, S., Killgore, W., Kahn-Green, E., Conrad, A., & Kamimori, G. (2006). Caffeine administered to maintain overnight alertness does not disrupt performance during the daytime withdrawal period. In SLEEP, 29.
• Muckle, A., Killgore, D., & Killgore, W. (2006). Gender differences in the effects of stimulant medications on the ability to estimate unknown quantities when sleep deprived. In Sleep, 29.
• Murray, C., Newman, R., O'Sullivan, M., Killgore, D., Balkin, T., & Killgore, W. (2006). Individual differences in stress management capacity predict responsiveness to caffeine during sleep deprivation. In Sleep, 29.
• Newman, R., Kamimori, G., & Killgore, W. (2006). Sleep deprivation diminishes constructive thinking. In SLEEP, 29.
• O'Sullivan, M., Reichardt, R., Krugler, A., Killgore, D., & Killgore, W. (2006). Premorbid intelligence correlates with duration and quality of recovery sleep following sleep deprivation. In SLEEP, 29.
• Reichardt, R., Killgore, D., Lipizzi, E., Li, C., Krugler, A., & Killgore, W. (2006). The effects of stimulants on recovery sleep and post-recovery verbal performance following 61-hours of sleep deprivation. In SLEEP, 29.
• Richards, J., & Killgore, W. (2006). The effect of caffeine, dextroamphetamine, and modafinil on alertness and mood during sleep deprivation. In Sleep, 29.
• Richards, J., Killgore, D., & Killgore, W. (2006). The effect of 44 hours of sleep deprivation on mood using the Visual Analog Mood Scales. In Sleep, 29.
• Kendall, A., Killgore, W., Kautz, M., & Russo, M. (2005). Left-visual field deficits in attentional processing after 40 hrs of sleep deprivation. In SLEEP, 28.
• Killgore, D., McBride, S., Balkin, T., & Killgore, W. (2005). Post-stimulant hangover: The effects of caffeine, modafinil, and dextroamphetamine on sustained verbal fluency following sleep deprivation and recovery sleep. In SLEEP, 28.
• Killgore, W., Balkin, T., & Wesensten, N. (2005). Impaired decision-making following 49 hours of sleep deprivation. In SLEEP, 28.
• Killgore, W., McBride, S., Killgore, D., & Balkin, T. (2005). Stimulant countermeasures and risk propensity across 2 nights of sleep deprivation. In SLEEP, 28.
• Vo, A., Green, J., Killgore, W., Sing, H., Labutta, R., & Redmond, D. (2005). The quantification of disrupted sleep in migraine via actigraphy: A Pilot Study. In SLEEP, 28.
• Killgore, W., Braun, A., Belenky, G., Wesensten, N., & Balkin, T. (2004). Regional cerebral metabolic correlates of electroencephalographic activity during stage-2 and slow wave sleep: An H215OPET study. In SLEEP, 27.
• Killgore, W., Reichardt, R., Kautz, M., Belenky, G., Balkin, T., & Wesensten, N. (2003). Daytime melatonin-zolpidem cocktail: III. Effects on salivary melatonin and performance. In SLEEP, 26.
• Kanayama, G., Killgore, W., Gruber, S., & Yurgelun-Todd, D. (2001). fMRI bold activation of the supramarginal gyrus in schizophrenia. In SCHIZOPHRENIA RESEARCH, 49.
• Yurgelun-Todd, D., Gruber, S., Killgore, W., & Young, A. (2001). Differential fMRI activation in bipolar patients during affect discrimination. In BIOLOGICAL PSYCHIATRY, 49.
• Killgore, W., Casanto, D., Maldjian, J., Alsop, D., Glosser, G., French, J., & Detre, J. (1999). Functional activation of mesial temporal lobe during nonverbal encoding. In EPILEPSIA, 40.

Poster Presentations

• Grandner, M., Alfonso-Miller, P., Warlick, C., Killgore, W., Taylor-Piliae, R. E., & Jajoo, A. (2019, Spring). Types of Habitual Physical Activity Associated with Habitual Sleep Duration, Sleep Quality, and Daytime Sleepiness.. Sleep 2019: 33rd Annual Meeting of the Associated Professional Sleep Societies.. San Antonio, TX..