Ulises Ricoy

Interests

Research

learning and memory, invertebrate models of drug reward, cultural responsive mentoring via low cost approaches in Neuroscience, First Year retention

Teaching

Neurobiology of Learning and Memory Behavioral NeuroscienceDrugs of AbuseNeurophysiology

Courses

Scholarly Contributions

Journals/Publications

• Ricoy, U. M., & Ramadan, B. (2023). The NEURON Program: Utilizing Low-Cost Neuroscience for Remote Education Outreach. Journal of Undergraduate Neuroscience Education.
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  The Neuroscience Education, Undergraduate Research, Outreach, and Networking (NEURON) Program provided first-year undergraduate students at the University of Arizona the opportunity to work with students from an inner-city Arizona high school. This work served as a continuation of the Grass Foundation’s Neuroscience Outreach workshops. We provided three weeks of distance-learning programming, which taught students about principles of neuroscience and neurophysiology. A special focus was the recruitment of students of diverse backgrounds and historically underrepresented minority (URM) students. We sought to address some of the historical disenfranchisement and program attrition within the University of Arizona Neuroscience and Cognitive Science undergraduate program (NSCS). Through recruiting and working in a disadvantaged school system, Peer-mentoring practices were leveraged to deliver four separate experimental opportunities to historically underserved groups. The high school we partnered with is historically underserved as a Title I school, meaning that 40% of its family population fall below the United States Federal Poverty Line. Critical to this program was providing hands-on opportunities to students who were undergoing distance-based learning due to the COVID-19 pandemic. Socially-distanced delivery of equipment to students allowed for equipment to be operated disparately by undergraduate mentors and high school mentees. A rotating system was applied so that mentees worked with a different mentor team each week on a given project. The NEURON program met its outcomes aimed at fostering both mentors and mentees as burgeoning scientists.
• Ricoy, U. M., Torres, D. J., Romero, A., & Colgan, W. (2021). A low-cost computational approach to analyze spiking activity in cockroach sensory neurons. Advances in Physiology Education, 45(1), 145-153. doi:10.1152/advan.00034.2020
• Torres, D. J., Romero, A., Colgan, W., & Ricoy, U. M. (2021). A low-cost computational approach to analyze spiking activity in cockroach sensory neurons. Advances in physiology education, 45(1), 145-153.
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  Undergraduates use a spike sorting routine developed in Octave to analyze the spiking activity generated from mechanical stimulation of spines of cockroach legs with the inexpensive SpikerBox amplifier and the free software Audacity. Students learn the procedures involved in handling the cockroaches and recording extracellular action potentials (spikes) with the SpikerBox apparatus as well as the importance of spike sorting for analysis in neuroscience. The spike sorting process requires students to choose the spike threshold and spike selection criteria and interact with the clustering process that forms the groups of similar spikes. Once the spike groups are identified, interspike intervals and neuron firing frequencies can be calculated and analyzed. A classic neurophysiology lab exercise is thus adapted to be interdisciplinary for underrepresented students in a small rural college.
• Franco, D., Zamudio, J., Blevins, K. M., Núñez-Larios, E. A., Ricoy, U. M., Iñiguez, S. D., & Zavala, A. R. (2020). Early-life ketamine exposure attenuates the preference for ethanol in adolescent Sprague-Dawley rats. Behavioural brain research, 389, 112626.
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  Ketamine, a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, produces quick and effective antidepressant results in depressed juvenile and adult individuals. The long-term consequences of using ketamine in juvenile populations are not well known, particularly as it affects vulnerability to drugs of abuse later in life, given that ketamine is also a drug of abuse. Thus, the current study examined whether early-life ketamine administration produces long-term changes in the sensitivity to the rewarding effects of ethanol, as measured using the conditioned place preference (CPP) paradigm. On postnatal day (PD) 21, juvenile male and female rats were pretreated with ketamine (0.0 or 20 mg/kg) for 10 consecutive days (i.e., PD 21-30) and then evaluated for ethanol-induced CPP (0.0, 0.125, 0.5, or 2.0 g/kg) from PD 32-39. Results revealed that early-life ketamine administration attenuated the rewarding properties of ethanol in male rats, as ketamine pretreated rats failed to exhibit ethanol-induced CPP at any dose compared to saline pretreated rats, which showed an increased preference towards the ethanol-paired compartment in a dose-dependent manner. In females, ethanol-induced CPP was generally less robust compared to males, but ketamine pretreatment resulted in a rightward shift in the dose-response curve, given that ketamine pretreated rats needed a higher dose of ethanol compared to saline pretreated rats to exhibit ethanol-induced CPP. When considered together, the findings suggest that early use of ketamine does not appear to enhance the vulnerability to ethanol later in life, but in contrast, it may attenuate the rewarding effects of ethanol.
• Torres, D. J., Cannon, J. L., Ricoy, U. M., & Johnson, C. (2016). Self-Contained Statistical Analysis of Gene Sets. PloS one, 11(10), e0163918.
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  Microarrays are a powerful tool for studying differential gene expression. However, lists of many differentially expressed genes are often generated, and unraveling meaningful biological processes from the lists can be challenging. For this reason, investigators have sought to quantify the statistical probability of compiled gene sets rather than individual genes. The gene sets typically are organized around a biological theme or pathway. We compute correlations between different gene set tests and elect to use Fisher's self-contained method for gene set analysis. We improve Fisher's differential expression analysis of a gene set by limiting the p-value of an individual gene within the gene set to prevent a small percentage of genes from determining the statistical significance of the entire set. In addition, we also compute dependencies among genes within the set to determine which genes are statistically linked. The method is applied to T-ALL (T-lineage Acute Lymphoblastic Leukemia) to identify differentially expressed gene sets between T-ALL and normal patients and T-ALL and AML (Acute Myeloid Leukemia) patients.
• Torres, D. J., Ricoy, U. M., & Roybal, S. (2015). Modeling Honey Bee Populations. PloS one, 10(7), e0130966.
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  Eusocial honey bee populations (Apis mellifera) employ an age stratification organization of egg, larvae, pupae, hive bees and foraging bees. Understanding the recent decline in honey bee colonies hinges on understanding the factors that impact each of these different age castes. We first perform an analysis of steady state bee populations given mortality rates within each bee caste and find that the honey bee colony is highly susceptible to hive and pupae mortality rates. Subsequently, we study transient bee population dynamics by building upon the modeling foundation established by Schmickl and Crailsheim and Khoury et al. Our transient model based on differential equations accounts for the effects of pheromones in slowing the maturation of hive bees to foraging bees, the increased mortality of larvae in the absence of sufficient hive bees, and the effects of food scarcity. We also conduct sensitivity studies and show the effects of parameter variations on the colony population.
• Ricoy, U. M., & Frerking, M. E. (2014). Distinct roles for Cav2.1-2.3 in activity-dependent synaptic dynamics. Journal of neurophysiology, 111(12), 2404-13.
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  Synaptic transmission throughout most of the CNS is steeply dependent on presynaptic calcium influx through the voltage-gated calcium channels Cav2.1-Cav2.3. In addition to triggering exocytosis, this calcium influx also recruits short-term synaptic plasticity. During the complex patterns of presynaptic activity that occur in vivo, several forms of plasticity combine to generate a synaptic output that is dynamic, in which the size of a given excitatory postsynaptic potential (EPSP) in response to a given spike depends on the short-term history of presynaptic activity. It remains unclear whether the different Cav2 channels play distinct roles in defining these synaptic dynamics and, if so, under what conditions different Cav2 family members most effectively determine synaptic output. We examined these questions by measuring the effects of calcium channel-selective toxins on synaptic transmission at the Schaffer collateral synapse in hippocampal slices from adult mice in response to both low-frequency stimulation and complex stimulus trains derived from in vivo recordings. Blockade of Cav2.1 had a greater inhibitory effect on synaptic transmission during low-frequency components of the stimulus train than on synaptic transmission during high-frequency components of the train, indicating that Cav2.1 had a greater fractional contribution to synaptic transmission at low frequencies than at high frequencies. Relative to Cav2.1, Cav2.2 had a disproportionately reduced contribution to synaptic transmission at frequencies >20 Hz, while Cav2.3 had a disproportionately increased contribution to synaptic transmission at frequencies >1 Hz. These activity-dependent effects of different Cav2 family members shape the filtering characteristics of GABAB receptor-mediated presynaptic inhibition. Thus different Cav2 channels vary in their coupling to synaptic transmission over different frequency ranges, with consequences for the frequency tuning of both synaptic dynamics and presynaptic neuromodulation.
• Fry, H. C., Garcia, J. M., Medina, M. J., Ricoy, U. M., Gosztola, D. J., Nikiforov, M. P., Palmer, L. C., & Stupp, S. I. (2012). Self-assembly of highly ordered peptide amphiphile metalloporphyrin arrays. Journal of the American Chemical Society, 134(36), 14646-9.
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  Long fibers assembled from peptide amphiphiles capable of binding the metalloporphyrin zinc protoporphyrin IX ((PPIX)Zn) have been synthesized. Rational peptide design was employed to generate a peptide, c16-AHL(3)K(3)-CO(2)H, capable of forming a β-sheet structure that propagates into larger fibrous structures. A porphyrin-binding site, a single histidine, was engineered into the peptide sequence in order to bind (PPIX)Zn to provide photophysical functionality. The resulting system indicates control from the molecular level to the macromolecular level with a high order of porphyrin organization. UV/visible and circular dichroism spectroscopies were employed to detail molecular organization, whereas electron microscopy and atomic force microscopy aided in macromolecular characterization. Preliminary picosecond transient absorption data are also reported. Reduced hemin, (PPIX)Fe(II), was also employed to highlight the material's versatility and tunability.
• Ricoy, U. M., Mao, P., Manczak, M., Reddy, P. H., & Frerking, M. E. (2011). A transgenic mouse model for Alzheimer's disease has impaired synaptic gain but normal synaptic dynamics. Neuroscience letters, 500(3), 212-5.
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  The chronic accumulation of amyloid beta (Aβ) peptides is thought to underlie much of the pathology of Alzheimer's disease (AD), and transgenic mice overexpressing Aβ show both behavioral defects and impairments in hippocampal synaptic transmission. In the present study, we examined excitatory transmission at the Schaffer collateral synapse in acute hippocampal slices from APP(Swe)/PS-1(A246E) transgenic mice to determine whether the synaptic impairment in these mice is due to a reduction in the activity-independent synaptic gain, or to a change in the activity-dependent synaptic dynamics. We observed a strong reduction in synaptic transmission in slices from APP(Swe)/PS-1(A246E) mice compared to those from their wildtype littermates. However, there was no resolvable change in the synaptic dynamics observed in response to either simple or complex stimulus trains. We conclude that the chronic accumulation of Aβ impairs synaptic transmission through a reduction in the synaptic gain, while preserving the synaptic dynamics.
• Ricoy, U. M., & Martinez, J. L. (2009). Local hippocampal methamphetamine-induced reinforcement. Frontiers in behavioral neuroscience, 3, 47.
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  Drug abuse and addiction are major problems in the United States. In particular methamphetamine (METH) use has increased dramatically. A greater understanding of how METH acts on the brain to induce addiction may lead to better therapeutic targets for this problem. The hippocampus is recognized as an important structure in learning and memory, but is not typically associated with drug reinforcement or reward processes. Here, the focus is on the hippocampus which has been largely ignored in the addiction literature as compared to the nucleus accumbens (NAc), ventral tegmental area (VTA), and prefrontal cortex (PFC). The results show that METH administered unilaterally via a microdialysis probe to rats' right dorsal hippocampus will induce drug-seeking (place preference) and drug-taking (lever-pressing) behavior. Furthermore, both of these responses are dependent on local dopamine (DA) receptor activation, as they are impaired by a selective D(1)/D(5) receptor antagonist. The results suggest that the hippocampus is part of the brain's reward circuit that underlies addiction.

Proceedings Publications

• Ricoy, U. (2017). Computer models for ions under electric and magnetic fields: Random walks and relocation of calcium in dendrites depends on timing and population type. In IFMBE Proceedings.

Presentations

• Ricoy, U. M. (2022, September 2022). Culturally Responsive Mentoring via Low-Cost Approaches in Neuroscience to Increase Retention. Centering Servingness. UArizona: UA HSI.
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  Dr. Ulises Ricoy's teaching, research, outreach, and leadership practices at the University of Arizona are focused on serving underrepresented (URM) students through culturally enhancing, equitable approached that offer transformative experiences leading to both academic (e.g., course completion, graduation, post-graduation jobs) and non-academic (e.g., science identity, aspirations, leadership) outcomes, The vehicle Dr.Ricoy has used to reach URM populations utilizes low-cost research/education approaches in neurophysiology/neuroethology.