Stuart R Hameroff
- Professor, Anesthesiology - (Clinical Scholar Track)
- Professor, Psychology
Stuart Hameroff MD grew up in Cleveland, Ohio, working summers at Republic Steel and Cleveland Stadium. At the University of Pittsburgh in the late 1960s, he studied chemistry, physics, mathematics and philosophy of mind. In medical school in the early 1970s at Hahnemann Medical College in Philadelphia, Hameroff spent a summer in a cancer research lab. Studying mitosis, he became interested in mitotic spindles and centrioles, composed of microtubules, polymers of the protein ‘tubulin’, and major components of the cytoskeleton within all cells. Comparing their lattice structure to Boolean computer matrices, he proposed that microtubules were the source of biological intelligence, and perhaps consciousness. Choosing an academic career, Hameroff trained in anesthesiology at the new University of Arizona Medical Center in Tucson, mentored by the department of anesthesiology’s founding chair, Dr Burnell Brown Jr, MD, PhD. After residency, Hameroff joined the anesthesiology faculty in 1977, a position he still holds as emeritus professor and practicing anesthesiologist.
Hameroff’s research pursues theory - brain mechanisms of consciousness, memory, anesthetic action, quantum processing in microtubules, and clinical applications - transcranial ultrasound (TUS) for various brain disorders.
In the mid 1990s Hameroff teamed with famed British physicist Sir Roger Penrose to develop a quantum theory of consciousness (‘orchestrated objective reduction’, ‘Orch OR’) based on microtubule quantum computing. Highly controversial and harshly criticized, Orch OR is now supported by evidence, e.g. that anesthetics act in quantum channels in microtubules, and that microtubules have multi-scalar resonances, e.g. in megahertz. Hameroff and Penrose wrote a 20 year review of Orch OR in 2014. Roger Penrose, is a frequent visitor to Tucson and the UA, thanks to his 28-year collaboration and friendship with Dr. Hameroff, and his association with the UA’s Center for Consciousness Studies. In 2020, Penrose was this year’s co-recipient of the Nobel Prize in Physics, Since 2001, Penrose and Stuart Hameroff have been collaborating on the Orch OR theory of how microtubules could “orchestrate” quantum computing leading to OR and consciousness. Penrose shared the 2020 Nobel prize in physics for showing that black holes are predictions of Einstein’s general relativity. Penrose has also proposed a solution to the measurement problem in quantum mechanics (‘objective reduction’, ‘OR’), which he suggests is also the origin of consciousness, leading to a theory of brain function (‘orchestrated objective reduction’, ‘Orch OR’). And Roger’s concept of Cyclical Conformal Cosmology (‘CCC’) posits a serial, eternal universe, with the Big Bang preceded by a previous aeon which had its own Big Bang, that aeon preceded by another and so on. Collaboration between Hameroff and Penrose continues on the theory.
SEMA Lab: UA/CCS: Transcranial Focused Ultrasound to the right prefrontal cortex - Megahertz mechanical vibrations are ultrasound, clinically used in anesthesiology, and Hameroff proposed low intensity, non-invasive ultrasound could stimulate microtubule megahertz resonance and improve mental and neurological states in the brain. He and anesthesiology colleagues performed and published the first clinical trial of transcranial ultrasound (‘TUS’) on mental states in human volunteers, showing mood enhancement from brief, low intensity TUS. Collaborative studies with psychology professor John JB Allen and post-doc Jay Sanguinetti corroborated and elaborated TUS effects, and more TUS clinical studies are planned for Alzheimer’s disease, depression, traumatic brain injury (with Dr. Lemole in neurosurgery), Parkinsons (Dr. Scott Sherman in Neurology) and pediatric developmental delay (with Dr. Sydney Rice in pediatrics). The group will test a state-of-the-art TUS headset from Berkeley Ultrasound, sponsored and organized through the Center for Consciousness Studies.
Beginning in 1994, with professor and former department head Al Kaszniak in Psychology, the late professor Alwyn Scott in mathematics, and subsequently philosophy (and Regents) professor David Chalmers, Hameroff started an interdisciplinary, international conference series ‘Toward a Science of Consciousness’ held in even-numbered years in Tucson, and odd-numbered years elsewhere around the world. April 2014 marked the 20 year anniversary ‘Tucson’ conference, and the 2015 conference will be in in Helsinki, Finland in June.
In 1998, with Kaszniak and Scott, and a 1.4 million dollar grant from the Fetzer Institute, Hameroff co-founded the University of Arizona Center for Consciousness Studies (CCS), served as associate director, and succeeded Kaszniak and then Chalmers, as director in 2004. With CCS moving administratively to anesthesiology, and Abi Behar-Montefiore as assistant director, CCS has subsisted since 2004 entirely on conference registration fees and small grants, and has supported relevant research.
Hameroff also collaborates with professors Jack Tuszynski at the University of Alberta, and Travis Craddock at Nova Southeastern on molecular modeling of microtubules, memory via CaMKII phosphorylation, and non-polar anesthetic and psychoactive drug actions in microtubule ‘quantum channels’. Quantum non-locality implied for consciousness has attracted interaction with Deepak Chopra, and the inaugural ‘Rustum Roy’ award to Hameroff in 2011.
Hameroff has written or edited 5 books, over a hundred scientific articles and book chapters, lectured around the world, and appeared in the film ‘WhattheBleep?’ and numerous TV shows about consciousness on BBC, PBS, Discovery, OWN and History Channel.
New Quantum website: https://phoenix.sbs.arizona.edu/quantum/
Center for Consciousness Studies http://www.consciousness.arizona.edu.
- M.D. Medical Degree
- Hahnemann Medical College, Philadelphia, Pennsylvania, United States
- B.S. Chemistry, Physics, Mathematics
- University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- University of Arizona, Tucson, Arizona (2004 - Ongoing)
- University of Ariona (2003 - Ongoing)
- University of Arizona, Tucson, Arizona (1999)
- University of Arizona, Tucson, Arizona (1998)
- University of Arizona, Tucson, Arizona (1995)
- University Medical Center (1995)
- University Medical Center (1994)
- University Medical Center (1984 - 1995)
- University Medical Center (1979 - 1985)
- University of Arizona, College of Medicine (1978 - 1984)
- University Hospital, University Medical Center, University Physicians Inc., University of Arizona, Health Sciences Center, UAHN, Banner-University Medical Center, The University of Arizona (1977 - Ongoing)
- University of Arizona, College of Medicine (1977 - 1978)
Licensure & Certification
- American Board of Anesthesiology (1979)
No activities entered.
Honors ThesisPSIO 498H (Spring 2017)
Honors ThesisPSIO 498H (Fall 2016)
- Hameroff, S. R., Kaszniak, A., & Chalmers, D. (1999). Toward a Science of Consciousness: The Third Tucson Discussions and Debates.
- Hameroff, S. R., Kaszniak, A., & Scott, A. (1998). Toward a Science of Consciousness II: The Second Tucson Discussions and Debates.
- Hameroff, S. R., Kaszniak, A., & Scott, A. (1996). Toward a Science of Consciousness: The First Tucson Discussion and Debates.
- Koruga, D., Hameroff, S. R., Withers, J., Loutfy, R., & Sundareshan, M. (1993). C60 Fullerene-From Nanobiology to Nanotechnology.
- Hameroff, S. R. (2019). Craddock, T.J., Kurian P., Tuszynski J.A., & Hameroff S.R. “Quantum Processes in Neurophotonics and the Origin of the Brain's Spatiotemporal Hierarchy.”. In Neurophotonics and Biomedical Spectroscopy (189-213); R.R. Alfano & L. Shi (Eds.). Amsterdam, Netherlands: Elsevier.
- Hameroff, S. R. (2019). Quantum Processes in Neurophotonics and the Origin of the Brain's Spatiotemporal Hierarchy. In Neurophotonics and Biomedical Spectroscopy(pp 189-213). Elsevier.
- Hameroff, S. R. (2018). Nonlinear amplification of quantum processes in neurophotonics and the origin of the brain's spatiotemporal heirarchy. In Neurophotonics and Biomedical Spectroscopy. Elsevier.
- Alfonseca, A. O., de la Cruz, M., Hameroff, S. R., & Lahoz-Beltra, R. (2015). A model of quantum-van Neumann hybrid cellular automata: Principles and simulation of quantum coherent superposition and decoherence in cytoskeletal microtubules. In Quantum Information and Computation.
- Ebner, M., & Hameroff, S. R. (2015). Modeling figure/ground separation with spiking neurons. In Simulations in Medicine.
- Hameroff, S. R. (2015). The quantum origin of life-How the brain evolved to feel good. In On Human Nature.
- Hameroff, S. R. (2014). Consciousness, Free Will and Quantum Brain Biology-The Orch OR Theory. In Quantum Physics Meets for Philosophy of Mind.
- Sanguinettl, J., Smith, E., Allen, J. J., & Hameroff, S. R. (2014). Human Brain Stimulation with Transcranial Ultrasound: Potential Applications for Mental Health. In Bioelectromagnetic and Subtle Energy Medicine.
- Hameroff, S. R. (1987). Ultimate Computing. In Biomolecular Consciousness and Nano Technology.
- Hameroff, S. (2020). 'Orch OR' is the most complete, and most easily falsifiable theory of consciousness. Cognitive neuroscience, 1-3.More infoThe 'Orch OR' theory attributes consciousness to quantum computations in microtubules inside brain neurons. Quantum computers process information as superpositions of multiple possibilities (quantum bits or qubits) which, in Orch OR, are alternative collective dipole oscillations orchestrated ('Orch') by microtubules. These orchestrated oscillations entangle, compute, and terminate ('collapse of the wavefunction') by Penrose objective reduction ('OR'), resulting in sequences of Orch OR moments with orchestrated conscious experience (metaphorically more like music than computation). Each Orch OR event selects microtubule states which govern neuronal functions. Orch OR has broad explanatory power, and is easily falsifiable.
- Hameroff, S. R. (2019). Transcranial focused ultrasound (tFUS) over the right prefrontal cortex improves mood and alters functional connectivity in humans. submitted.More infoSanguinetti JL, Hameroff S, Smith EE, Dieckman LW, Sato T, Daft CMW, Tyler WJ, Allen JJB (2019) Transcranial focused ultrasound (tFUS) over the right prefrontal cortex improves mood and alters functional connectivity in humans (submitted)
- Sanguinetti, J. L., Hameroff, S., Smith, E. E., Sato, T., Daft, C. M., Tyler, W. J., & Allen, J. J. (2020). Transcranial Focused Ultrasound to the Right Prefrontal Cortex Improves Mood and Alters Functional Connectivity in Humans. Frontiers in human neuroscience, 14, 52.More infoTranscranial focused ultrasound (tFUS) is an emerging method for non-invasive neuromodulation akin to transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). tFUS offers several advantages over electromagnetic methods including high spatial resolution and the ability to reach deep brain targets. Here we describe two experiments assessing whether tFUS could modulate mood in healthy human volunteers by targeting the right inferior frontal gyrus (rIFG), an area implicated in mood and emotional regulation. In a randomized, placebo-controlled, double-blind study, participants received 30 s of 500 kHz tFUS or a placebo control. Visual Analog Mood Scales (VAMS) assessed mood four times within an hour (baseline and three times after tFUS). Participants who received tFUS reported an overall increase in Global Affect (GA), an aggregate score from the VAMS scale, indicating a positive shift in mood. Experiment 2 examined resting-state functional (FC) connectivity using functional magnetic resonance imaging (fMRI) following 2 min of 500 kHz tFUS at the rIFG. As in Experiment 1, tFUS enhanced self-reported mood states and also decreased FC in resting state networks related to emotion and mood regulation. These results suggest that tFUS can be used to modulate mood and emotional regulation networks in the prefrontal cortex.
- Hameroff, S. R. (2019). Consciousness and quantum state reduction - Which Comes First?. Activitas Nervosa Superior, Volume 61, Issue 1–2, pp 31–40.
- Hameroff, S. R. (2018). Anesthetic Action and "Quantum Consciousness": A Match Made in Olive Oil. Anesthesiology, 129(2), 228-231.
- Hameroff, S. R. (2018). Journal of Consciousness Studies. Journal of Consciousness Studies.
- Craddock, T. J., Kurian, P., Preto, J., Sahu, K., Hameroff, S. R., Klobukowski, M., & Tuszynski, J. A. (2017). Anesthetic Alterations of Collective Terahertz Oscillations in Tubulin Correlate with Clinical Potency: Implications for Anesthetic Action and Post-Operative Cognitive Dysfunction. Scientific reports, 7(1), 9877.More infoAnesthesia blocks consciousness and memory while sparing non-conscious brain activities. While the exact mechanisms of anesthetic action are unknown, the Meyer-Overton correlation provides a link between anesthetic potency and solubility in a lipid-like, non-polar medium. Anesthetic action is also related to an anesthetic's hydrophobicity, permanent dipole, and polarizability, and is accepted to occur in lipid-like, non-polar regions within brain proteins. Generally the protein target for anesthetics is assumed to be neuronal membrane receptors and ion channels, however new evidence points to critical effects on intra-neuronal microtubules, a target of interest due to their potential role in post-operative cognitive dysfunction (POCD). Here we use binding site predictions on tubulin, the protein subunit of microtubules, with molecular docking simulations, quantum chemistry calculations, and theoretical modeling of collective dipole interactions in tubulin to investigate the effect of a group of gases including anesthetics, non-anesthetics, and anesthetic/convulsants on tubulin dynamics. We found that these gases alter collective terahertz dipole oscillations in a manner that is correlated with their anesthetic potency. Understanding anesthetic action may help reveal brain mechanisms underlying consciousness, and minimize POCD in the choice and development of anesthetics used during surgeries for patients suffering from neurodegenerative conditions with compromised cytoskeletal microtubules.
- Craddock, T. J., Hameroff, S. R., Ayoub, A. T., Klobukowski, M., Tuszynski, J. A., Craddock, T. J., Hameroff, S. R., Ayoub, A. T., Klobukowski, M., & Tuszynski, J. A. (2015). Anesthetics act in quantum channels in brain microtubules to prevent consciousness. Current topics in medicinal chemistry, 15(6), 523-33.More infoThe mechanism by which anesthetic gases selectively prevent consciousness and memory (sparing non-conscious brain functions) remains unknown. At the turn of the 20(th) century Meyer and Overton showed that potency of structurally dissimilar anesthetic gas molecules correlated precisely over many orders of magnitude with one factor, solubility in a non-polar, 'hydrophobic' medium akin to olive oil. In the 1980s Franks and Lieb showed anesthetics acted in such a medium within proteins, suggesting post-synaptic membrane receptors. But anesthetic studies on such proteins yielded only confusing results. In recent years Eckenhoff and colleagues have found anesthetic action in microtubules, cytoskeletal polymers of the protein tubulin inside brain neurons. 'Quantum mobility' in microtubules has been proposed to mediate consciousness. Through molecular modeling we have previously shown: (1) olive oil-like non-polar, hydrophobic quantum mobility pathways ('quantum channels') of tryptophan rings in tubulin, (2) binding of anesthetic gas molecules in these channels, and (3) capabilities for π-electron resonant energy transfer, or exciton hopping, among tryptophan aromatic rings in quantum channels, similar to photosynthesis protein quantum coherence. Here, we show anesthetic molecules can impair π-resonance energy transfer and exciton hopping in tubulin quantum channels, and thus account for selective action of anesthetics on consciousness and memory.
- Craddock, T. J., Friesen, D., Mane, J., Hameroff, S., & Tuszynski, J. A. (2014). The feasibility of coherent energy transfer in microtubules. Journal of the Royal Society, Interface / the Royal Society, 11(100), 20140677.More infoIt was once purported that biological systems were far too 'warm and wet' to support quantum phenomena mainly owing to thermal effects disrupting quantum coherence. However, recent experimental results and theoretical analyses have shown that thermal energy may assist, rather than disrupt, quantum coherent transport, especially in the 'dry' hydrophobic interiors of biomolecules. Specifically, evidence has been accumulating for the necessary involvement of quantum coherent energy transfer between uniquely arranged chromophores in light harvesting photosynthetic complexes. The 'tubulin' subunit proteins, which comprise microtubules, also possess a distinct architecture of chromophores, namely aromatic amino acids, including tryptophan. The geometry and dipolar properties of these aromatics are similar to those found in photosynthetic units indicating that tubulin may support coherent energy transfer. Tubulin aggregated into microtubule geometric lattices may support such energy transfer, which could be important for biological signalling and communication essential to living processes. Here, we perform a computational investigation of energy transfer between chromophoric amino acids in tubulin via dipole excitations coupled to the surrounding thermal environment. We present the spatial structure and energetic properties of the tryptophan residues in the microtubule constituent protein tubulin. Plausibility arguments for the conditions favouring a quantum mechanism of signal propagation along a microtubule are provided. Overall, we find that coherent energy transfer in tubulin and microtubules is biologically feasible.
- Hameroff, S. (2014). Quantum walks in brain microtubules--a biomolecular basis for quantum cognition?. Topics in cognitive science, 6(1), 91-7.More infoCognitive decisions are best described by quantum mathematics. Do quantum information devices operate in the brain? What would they look like? Fuss and Navarro () describe quantum lattice registers in which quantum superpositioned pathways interact (compute/integrate) as 'quantum walks' akin to Feynman's path integral in a lattice (e.g. the 'Feynman quantum chessboard'). Simultaneous alternate pathways eventually reduce (collapse), selecting one particular pathway in a cognitive decision, or choice. This paper describes how quantum walks in a Feynman chessboard are conceptually identical to 'topological qubits' in brain neuronal microtubules, as described in the Penrose-Hameroff 'Orch OR' theory of consciousness.
- Hameroff, S. R. (2014). Consciousness, Microtubules and "Orch-OR": A 'Space-time' Odyessey'. Journal of Consciousness Studies.
- Hameroff, S. R. (2014). Consciousness, Microtubules and "Orch-OR": A 'Space-time' Odyssey'. Journal of Consciousness Studies.
- Hameroff, S. R. (2014). Quantum walks in brain microtubules-a biomolecular basisn for quantum congnition?. Topics in Cognitive Sciences.
- Hameroff, S. R., & Penrose, R. (2014). Reply to Criticism of the 'Orch OR qubit'-Orchestrated objective reduction is scientifically justified.. Physics of Life Reviews.
- Hameroff, S. R., & Penrose, R. (2014). Reply to Seven Commentaries on Consciousness in the Universe: Review of the 'Orch OR' Theory. Physics of Life Reviews.
- Hameroff, S. R., Craddock, T. J., & Tuszynski, J. A. (2014). Quantum effects in the understanding of consciousness. Journal of integrative neuroscience, 13(2), 229-52.More infoThis paper presents a historical perspective on the development and application of quantum physics methodology beyond physics, especially in biology and in the area of consciousness studies. Quantum physics provides a conceptual framework for the structural aspects of biological systems and processes via quantum chemistry. In recent years individual biological phenomena such as photosynthesis and bird navigation have been experimentally and theoretically analyzed using quantum methods building conceptual foundations for quantum biology. Since consciousness is attributed to human (and possibly animal) mind, quantum underpinnings of cognitive processes are a logical extension. Several proposals, especially the Orch OR hypothesis, have been put forth in an effort to introduce a scientific basis to the theory of consciousness. At the center of these approaches are microtubules as the substrate on which conscious processes in terms of quantum coherence and entanglement can be built. Additionally, Quantum Metabolism, quantum processes in ion channels and quantum effects in sensory stimulation are discussed in this connection. We discuss the challenges and merits related to quantum consciousness approaches as well as their potential extensions.
- Hameroff, S., & Penrose, R. (2014). Consciousness in the universe: a review of the 'Orch OR' theory. Physics of life reviews, 11(1), 39-78.More infoThe nature of consciousness, the mechanism by which it occurs in the brain, and its ultimate place in the universe are unknown. We proposed in the mid 1990's that consciousness depends on biologically 'orchestrated' coherent quantum processes in collections of microtubules within brain neurons, that these quantum processes correlate with, and regulate, neuronal synaptic and membrane activity, and that the continuous Schrödinger evolution of each such process terminates in accordance with the specific Diósi-Penrose (DP) scheme of 'objective reduction' ('OR') of the quantum state. This orchestrated OR activity ('Orch OR') is taken to result in moments of conscious awareness and/or choice. The DP form of OR is related to the fundamentals of quantum mechanics and space-time geometry, so Orch OR suggests that there is a connection between the brain's biomolecular processes and the basic structure of the universe. Here we review Orch OR in light of criticisms and developments in quantum biology, neuroscience, physics and cosmology. We also introduce a novel suggestion of 'beat frequencies' of faster microtubule vibrations as a possible source of the observed electro-encephalographic ('EEG') correlates of consciousness. We conclude that consciousness plays an intrinsic role in the universe.
- Hameroff, S. (2013). A tale of two fields: comment on "Dissipation of 'dark energy' by cortex in knowledge retrieval" by Capolupo, Freeman and Vitiello. Physics of life reviews, 10(1), 95-6; discussion 112-6.
- Hameroff, S. R. (2013). Quantum mathematical cognition requires quantum brain biology: the "Orch OR" theory. The Behavioral and brain sciences, 36(3), 287-90.More infoThe "Orch OR" theory suggests that quantum computations in brain neuronal dendritic-somatic microtubules regulate axonal firings to control conscious behavior. Within microtubule subunit proteins, collective dipoles in arrays of contiguous amino acid electron clouds enable "quantum channels" suitable for topological dipole "qubits" able to physically represent cognitive values, for example, those portrayed by Pothos & Busemeyer (P&B) as projections in abstract Hilbert space.
- Hameroff, S. R. (2013). Quantum mathematical cognition requires quantum brain biology: the "Orch OR" theory.. Behavioral and Brain Sciences.
- Hameroff, S. R., Trakas, M., Duffield, C., Annabi, E., Gerace, M., Boyle, P., Lucas, A., Amos, Q., Bauda, A., & Badal, J. (2013). Transcranial ultrasound (TUS) effects on mental states: a pilot study.. Brain Stimulation.
- Craddoc, T., St George, M., Freedman, H., Barakat, K., Darnaraju, S., Hameroff, S. R., & Tuszynski, J. (2012). Computational Predictions of Volatile Anesthetic Interactions with the Microtubule Cytoskeleton: Implications for Side Effects of General Anesthesia. Plos One.
- Craddock, T. J., Tuszynski, J. A., Chopra, D., Casey, N., Goldstein, L. E., Hameroff, S. R., & Tanzi, R. E. (2012). The zinc dyshomeostasis hypothesis of Alzheimer's disease. PloS one, 7(3), e33552.More infoAlzheimer's disease (AD) is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ), intracellular neurofibrillary tangles (NFTs) composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau), and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques) not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1) used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2) performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3) used metallomic imaging mass spectrometry (MIMS) to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of polymerized microtubules, their binding to MAP-tau, and molecular dynamics involved in cognition. Further, our theory supports novel AD therapeutic strategies targeting intra-neuronal zinc homeostasis and microtubule dynamics to prevent neurodegeneration and cognitive decline.
- Craddock, T., St George, M., Freedman, H., Barakat, K., Darnaraju, S., Hameroff, S. R., & Tuszynski, J. (2012). Computational predictions of volatile anesthetic interactions with the microtubule cytoskeleton: implications for side effects of general anesthesia.. PLos One.
- Craddock, T., Tuszynski, J., & Hameroff, S. R. (2012). Cytoskeletal Signaling: Is Memory Encoded in Microtubule Lattices by CaMKII Phosphorylation?. PLos Computational Biology.
- Craddock, T., Tuszynski, J., Chopra, D., Casey, N., Goldstein, L., Hameroff, S. R., & Tanzi, R. (2012). The zinc dyshomeostasis hypothesis of Alzheimer's disease.. PLos One.
- Hameroff, S. (2012). Quantum brain biology complements neuronal assembly approaches to consciousness: Comment on "Consciousness, biology and quantum hypotheses" by Baars and Edelman. Physics of life reviews, 9(3), 303-5; discussion 306-7.
- Hameroff, S. R. (2012). How quantum brain biology can rescue conscious free will.. Frontiers in Integrative Neuroscience.
- Ebner, M., & Hameroff, S. (2011). Lateral information processing by spiking neurons: a theoretical model of the neural correlate of consciousness. Computational intelligence and neuroscience, 2011, 247879.More infoCognitive brain functions, for example, sensory perception, motor control and learning, are understood as computation by axonal-dendritic chemical synapses in networks of integrate-and-fire neurons. Cognitive brain functions may occur either consciously or nonconsciously (on "autopilot"). Conscious cognition is marked by gamma synchrony EEG, mediated largely by dendritic-dendritic gap junctions, sideways connections in input/integration layers. Gap-junction-connected neurons define a sub-network within a larger neural network. A theoretical model (the "conscious pilot") suggests that as gap junctions open and close, a gamma-synchronized subnetwork, or zone moves through the brain as an executive agent, converting nonconscious "auto-pilot" cognition to consciousness, and enhancing computation by coherent processing and collective integration. In this study we implemented sideways "gap junctions" in a single-layer artificial neural network to perform figure/ground separation. The set of neurons connected through gap junctions form a reconfigurable resistive grid or sub-network zone. In the model, outgoing spikes are temporally integrated and spatially averaged using the fixed resistive grid set up by neurons of similar function which are connected through gap-junctions. This spatial average, essentially a feedback signal from the neuron's output, determines whether particular gap junctions between neurons will open or close. Neurons connected through open gap junctions synchronize their output spikes. We have tested our gap-junction-defined sub-network in a one-layer neural network on artificial retinal inputs using real-world images. Our system is able to perform figure/ground separation where the laterally connected sub-network of neurons represents a perceived object. Even though we only show results for visual stimuli, our approach should generalize to other modalities. The system demonstrates a moving sub-network zone of synchrony, within which the contents of perception are represented and contained. This mobile zone can be viewed as a model of the neural correlate of consciousness in the brain.
- Ebner, M., & Hameroff, S. R. (2011). Lateral information processing by spiking neurons: a theoretical model of the neural correlate of consciousness.. Computational Intelligence and Neuroscience.
- Hameroff, S. (2010). The "conscious pilot"-dendritic synchrony moves through the brain to mediate consciousness. Journal of biological physics, 36(1), 71-93.More infoCognitive brain functions including sensory processing and control of behavior are understood as "neurocomputation" in axonal-dendritic synaptic networks of "integrate-and-fire" neurons. Cognitive neurocomputation with consciousness is accompanied by 30- to 90-Hz gamma synchrony electroencephalography (EEG), and non-conscious neurocomputation is not. Gamma synchrony EEG derives largely from neuronal groups linked by dendritic-dendritic gap junctions, forming transient syncytia ("dendritic webs") in input/integration layers oriented sideways to axonal-dendritic neurocomputational flow. As gap junctions open and close, a gamma-synchronized dendritic web can rapidly change topology and move through the brain as a spatiotemporal envelope performing collective integration and volitional choices correlating with consciousness. The "conscious pilot" is a metaphorical description for a mobile gamma-synchronized dendritic web as vehicle for a conscious agent/pilot which experiences and assumes control of otherwise non-conscious auto-pilot neurocomputation.
- Hameroff, S. R. (2010). The "conscious-pilot" dendritic synchrony moves through the brain to mediate consciousness.. Journal of Biological Physics.
- Hameroff, S. R., Craddock, T. J., & Tuszynski, J. A. (2010). "Memory bytes" - molecular match for CaMKII phosphorylation encoding of microtubule lattices. Journal of integrative neuroscience, 9(3), 253-67.More infoLearning, memory and long-term potentiation (LTP) are supported by factors including post-synaptic calcium ion flux activating and transforming the hexagonal calcium-calmodulin kinase II (CaMKII) holoenzyme. Upon calcium-induced activation, up to six kinase domains extend upward, and up to six kinase domains extend downward from the CaMKII association domain, the fully activated holoenzyme resembling a robotic insect 20 nanometers in length. Each extended kinase domain can be phosphorylated, and able to phosphorylate other proteins, thus potentially further encoding synaptic information at intraneuronal molecular sites for memory storage, processing and distribution. Candidate sites for phosphorylation-encoded molecular memory include microtubules, cylindrical lattice polymers of the protein tubulin. Using molecular modeling, we find spatial dimensions and geometry of the six extended CaMKII kinase domains can precisely match those of microtubule hexagonal lattice neighborhoods (both A- and B-lattices), and show two feasible phosphorylation mechanisms. In one, phosphorylation sites (e.g., valine 208) on a CaMKII extended kinase domain interact with serine 444 on a C-terminal "tail" of tubulin. In the second, the CaMKII kinase domain unfurls, enabling phosphorylation sites to contact threonine and serine sites on the tubulin surface. We suggest sets of six CaMKII kinase domains phosphorylate hexagonal microtubule lattice neighborhoods collectively, e.g., conveying synaptic information as ordered arrays of six "bits", and thus a "byte", with (minimally) 2⁶ (64) possible bit states per CaMKII-microtubule interaction. We model two levels of interaction between CaMKII and microtubules, suggesting a testable framework for molecular memory encoding.
- Hameroff, S. R., Craddock, T., & Tuszynski, J. (2010). "Memory bytes" molecular match for CaMKII phosphorylation encoding of microtubule lattices.. Journal of Integrative Neurosciences.
- Hameroff, S. R. (2007). The Brain Is Both Neurocomputer and Quantum Computer. Cognitive Science.
- Hameroff, S. R. (2007). The Good, the Bad and the Octopus. Journal of Consciousness Studies.
- Hameroff, S. R. (2007). The brain is both neurocomputer and quantum computer. Cognitive science, 31(6), 1035-45.More infoIn their article, Is the Brain a Quantum Computer,? Litt, Eliasmith, Kroon, Weinstein, and Thagard (2006) criticize the Penrose-Hameroff "Orch OR" quantum computational model of consciousness, arguing instead for neurocomputation as an explanation for mental phenomena. Here I clarify and defend Orch OR, show how Orch OR and neurocomputation are compatible, and question whether neurocomputation alone can physiologically account for coherent gamma synchrony EEG, a candidate for the neural correlate of consciousness. Orch OR is based on quantum computation in microtubules within dendrites in cortex and other regions linked by dendritic-dendritic gap junctions ("dendritic webs") acting as laterally connected input layers of the brain's neurocomputational architecture. Within dendritic webs, consciousness is proposed to occur as gamma EEG-synchronized sequences of discrete quantum computational events acting in integration phases of neurocomputational "integrate-and-fire" cycles. Orch OR is a viable approach toward understanding how the brain produces consciousness.
- Hameroff, S. R. (2006). The entwined mysteries of anesthesia and consciousness: is there a common underlying mechanism?. Anesthesiology, 105(2), 400-12.
- Hameroff, S. R. (2006). The entwined mysteries of anesthesia and consciousness: is there a common underlying mechanism?. Anesthesiology.
- Hameroff, S. R. (2004). A new theory of the origin of cancer: quantum coherent entanglement, centrioles, mitosis, and differentiation. Bio Systems, 77(1-3), 119-36.More infoMalignant cells are characterized by abnormal segregation of chromosomes during mitosis ("aneuploidy"), generally considered a result of malignancy originating in genetic mutations. However, recent evidence supports a century-old concept that maldistribution of chromosomes (and resultant genomic instability) due to abnormalities in mitosis itself is the primary cause of malignancy rather than a mere byproduct. In normal mitosis chromosomes replicate into sister chromatids which are then precisely separated and transported into mirror-like sets by structural protein assemblies called mitotic spindles and centrioles, both composed of microtubules. The elegant yet poorly understood ballet-like movements and geometric organization occurring in mitosis have suggested guidance by some type of organizing field, however neither electromagnetic nor chemical gradient fields have been demonstrated or shown to be sufficient. It is proposed here that normal mirror-like mitosis is organized by quantum coherence and quantum entanglement among microtubule-based centrioles and mitotic spindles which ensure precise, complementary duplication of daughter cell genomes and recognition of daughter cell boundaries. Evidence and theory supporting organized quantum states in cytoplasm/nucleoplasm (and quantum optical properties of centrioles in particular) at physiological temperature are presented. Impairment of quantum coherence and/or entanglement among microtubule-based mitotic spindles and centrioles can result in abnormal distribution of chromosomes, abnormal differentiation and uncontrolled growth, and account for all aspects of malignancy. New approaches to cancer therapy and stem cell production are suggested via non-thermal laser-mediated effects aimed at quantum optical states of centrioles.
- Hameroff, S. R. (2004). A new theory of the origin of cancer: quantum coherent entanglement, centrioles, mitosis, and differentiation.. Biosystems.
- Hagan, S., Hameroff, S. R., & Tuszyński, J. A. (2002). Quantum computation in brain microtubules: decoherence and biological feasibility. Physical review. E, Statistical, nonlinear, and soft matter physics, 65(6 Pt 1), 061901.More infoThe Penrose-Hameroff orchestrated objective reduction (orch. OR) model assigns a cognitive role to quantum computations in microtubules within the neurons of the brain. Despite an apparently "warm, wet, and noisy" intracellular milieu, the proposal suggests that microtubules avoid environmental decoherence long enough to reach threshold for "self-collapse" (objective reduction) by a quantum gravity mechanism put forth by Penrose. The model has been criticized as regards the issue of environmental decoherence, and a recent report by Tegmark finds that microtubules can maintain quantum coherence for only 10(-13) s, far too short to be neurophysiologically relevant. Here, we critically examine the decoherence mechanisms likely to dominate in a biological setting and find that (1) Tegmark's commentary is not aimed at an existing model in the literature but rather at a hybrid that replaces the superposed protein conformations of the orch. OR theory with a soliton in superposition along the microtubule; (2) recalculation after correcting for differences between the model on which Tegmark bases his calculations and the orch. OR model (superposition separation, charge vs dipole, dielectric constant) lengthens the decoherence time to 10(-5)-10(-4) s; (3) decoherence times on this order invalidate the assumptions of the derivation and determine the approximation regime considered by Tegmark to be inappropriate to the orch. OR superposition; (4) Tegmark's formulation yields decoherence times that increase with temperature contrary to well-established physical intuitions and the observed behavior of quantum coherent states; (5) incoherent metabolic energy supplied to the collective dynamics ordering water in the vicinity of microtubules at a rate exceeding that of decoherence can counter decoherence effects (in the same way that lasers avoid decoherence at room temperature); (6) microtubules are surrounded by a Debye layer of counterions, which can screen thermal fluctuations, and by an actin gel that might enhance the ordering of water in bundles of microtubules, further increasing the decoherence-free zone by an order of magnitude and, if the dependence on the distance between environmental ion and superposed state is accurately reflected in Tegmark's calculation, extending decoherence times by three orders of magnitude; (7) topological quantum computation in microtubules may be error correcting, resistant to decoherence; and (8) the decohering effect of radiative scatterers on microtubule quantum states is negligible. These considerations bring microtubule decoherence into a regime in which quantum gravity could interact with neurophysiology.
- Hameroff, S. R., Nip, A., Porter, M., & Tuszynski, J. (2002). Conduction pathways in microtubules, biological quantum computation, and consciousness.. Biosystems.
- Hameroff, S. R. (2001). Consciousness, the brain and spacetime geometry.. Annals New York Academy of Sciences.
- Hameroff, S. R., & Woolf, N. (2001). A quantum approach to visual consciousness.. Trends in Cognitive Sciences.
- Woolf, N. J., & Hameroff, S. R. (2001). A quantum approach to visual consciousness. Trends in cognitive sciences, 5(11), 472-478.More infoA theoretical approach relying on quantum computation in microtubules within neurons can potentially resolve the enigmatic features of visual consciousness, but raises other questions. For example, how can delicate quantum states, which in the technological realm demand extreme cold and isolation to avoid environmental 'decoherence', manage to survive in the warm, wet brain? And if such states could survive within neuronal cell interiors, how could quantum states grow to encompass the whole brain? We present a physiological model for visual consciousness that can accommodate brain-wide quantum computation according to the Penrose-Hameroff 'Orch OR' model. In this view, visual consciousness occurs as a series of several-hundred-millisecond epochs, each comprising 'crescendo sequences' of quantum computations occurring at approximately 40 Hz.
- Hameroff, S. R. (1988). Quantum computation in brain microtubules? The Penrose-Hameroff "Orch-OR" model of consciousness.. Philosophical Transactions Royal Society London.
- Hameroff, S. R. (1998). Anesthesia, consciousness and hydrophobic pockets- a unitary quantum hypothesis of anesthetic action.. Toxicology Letters.
- Hameroff, S. R. (1998). Is the conscious mind subtly linked to a basic level of the universe?. Trends in Cognitive Sciences.
- Hameroff, S. R., & Penrose, R. (1996). Conscious events as orchestrated space time selections.. Journal of Consciousness Studies.
- Hameroff, S. R., & Penrose, R. (1996). Orchestrated reduction of quantum coherence in brain microtubules: a model for consciousness?. Mathematics and Computers in Simulation.
- Lahoz-Beltra, R., Hameroff, S. R., & Dayhoff, J. (1996). Connection weights based on molecular mechanisms in Aplysia neuron synapses. Neurocomputing.
- Lahoz-Beltra, R., Hameroff, S. R., Dayhoff, J., Shellie, K., & Mangan, R. (1996). Tolerance of red-fleshed grapefruit to a constant or stepped temperature, forced-air quarantine heat treatment.. Postharvest Biology and Technology.
- Lahoz-Beltra, R., Hameroff, S. R., Dayhoff, J., Shellie, K., Mangan, R., & Capoyleas, V. (1996). On the area of the intersection of disks in the plane.. Computational Geometry.
- Hameroff, S. R. (1995). What gaps? Reply to Grush and Churchland.. Journal of Consciousness Studies.
- Hameroff, S. R., & Penrose, R. (1995). Orchestrated reduction of quantum coherence in brain microtubules: a model for consciousness?. Neural Network World.
- Tuszynski, J., Hameroff, S. R., Satari, M., Trpisov, B., & Nip, M. (1995). Ferroelectric behavior in microtubule dipole lattices: implications for information processing,signaling and assembly/disassembly.. Journal of Theoretical Biology.
- Dayhoff, J., Hameroff, S., Lahoz-Beltra, R., & Swenberg, C. E. (1994). Cytoskeletal involvement in neuronal learning: a review. European biophysics journal : EBJ, 23(2), 79-93.More infoThis paper introduces the ideas of neural networks in the context of currently recognized cellular structures within neurons. Neural network models and paradigms require adaptation of synapses for learning to occur in the network. Some models of learning paradigms require information to move from axon to dendrite. This motivated us to examine the possibility of intracellular signaling to mediate such signals. The cytoskeleton forms a substrate for intracellular signaling via material transport and other putative mechanisms. Furthermore, many experimental results suggest a link between the cytoskeleton and cognitive processing. In this paper we review research on intracellular signaling in the context of neural network learning.
- Jibu, M., Hagan, S., Hameroff, S. R., Pribram, K. H., & Yasue, K. (1994). Quantum optical coherence in cytoskeletal microtubules: implications for brain function. Bio Systems, 32(3), 195-209.More info'Laser-like,' long-range coherent quantum phenomena may occur biologically within cytoskeletal microtubules. This paper presents a theoretical prediction of the occurrence in biological media of the phenomena which we term 'superradiance' and 'self-induced transparency'. Interactions between the electric dipole field of water molecules confined within the hollow core of microtubules and the quantized electromagnetic radiation field are considered, and microtubules are theorized to play the roles of non-linear coherent optical devices. Superradiance is a specific quantum mechanical ordering phenomenon with characteristic times much shorter than those of thermal interaction. Consequently, optical signalling (and computation) in microtubules would be free from both thermal noise and loss. Superradiant optical computing in networks of microtubules and other cytoskeletal structures may provide a basis for biomolecular cognition and a substrate for consciousness.
- Koruga, D., Simic-Krstic, J., Trifunovic, M., Jankovic, S., Hameroff, S. R., Withers, J., & Loutfy, R. (1993). Imaging fullerene C60 with atomic resolution using a scanning tunneling microscope.. Fullerene Science and Technology.
- Lahoz-Beltra, R., Hameroff, S. R., & Dayhoff, J. E. (1993). Cytoskeletal logic: a model for molecular computation via Boolean operations in microtubules and microtubule-associated proteins. Bio Systems, 29(1), 1-23.More infoAdaptive behaviors and dynamic activities within living cells are organized by the cytoskeleton: intracellular networks of interconnected protein polymers which include microtubules (MTs), actin, intermediate filaments, microtubule associated proteins (MAPs) and other protein structures. Cooperative interactions among cytoskeletal protein subunit conformational states have been used to model signal transmission and information processing. In the present work we present a theoretical model for molecular computing in which Boolean logic is implemented in parallel networks of individual MTs interconnected by MAPs. Conformational signals propagate on MTs as in data buses and in the model MAPs are considered as Boolean operators, either as bit-lines (like MTs) where a signal can be transported unchanged between MTs ('BUS-MAP'), or as bit-lines where a Boolean operation is performed in one of the two MAP-MT attachments ('LOGIC-MAP'). Three logic MAPs have been defined ('NOT-MAP, 'AND-MAP', 'XOR-MAP') and used to demonstrate addition, subtraction and other arithmetic operations. Although our choice of Boolean logic is arbitrary, the simulations demonstrate symbolic manipulation in a connectionist system and suggest that MT-MAP networks can perform computation in living cells and are candidates for future molecular computing devices.
- Hameroff, S. R., Dayhoff, J., Lahoz-Beltra, R., Sarnsonovich, A., & Rasmussen, S. (1992). Conformational automata in the cytoskeleton: Models for molecular computation.. IEEE Computer.
- Hotani, H., Beltra-Lahoz, R., Combs, B., Hameroff, S. R., & Rasmussen, S. (1992). Microtubule dynamics, liposomes and artificial cells: in vitro observation and cellular automata simulation of microtubule assembly/disassembly and membrane mocphogenesis.. Nanobiology.
- Sarnsonovich, A., Scott, A., & Hameroff, S. R. (1992). Acousta-conformational transitions in cytoskeletal microtubules: implications for intracellular information processing.. Nanobiology.
- Vernetti, L., Nowlin, C., Hameroff, S. R., Gandolfi, A., Lee, Y., & Sarid, D. (1991). Scanning tunneling microscopy resolutions of surface features on cytokeratin protein is enhanced by prolonged exposure of protein to cold temperatures. Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures..
- Hameroff, S. R., Simic-Krstic, Y., Vernetti, L., Lee, Y., Sarid, D., Weidmann, J., Elings, V., Kjoller, K., & McCuskey, R. (1990). STM of cytoskeletal proteins: Microtubules and intermediate filaments.. Journal of Vaccum Science and Technology.
- Hameroff, S. R., Schneiker, C., Voelker, M., He, J., Dereniak, E., & McCuskey, R. (1988). Scanning tunneling microscopy (STM) applications to molecular electronics, Engineering in Medicine and Biology Society.. Proceedings of the Annual International Conference of the Institute of Electrical and Electronics Engineers.
- Watt, R. C., & Hameroff, S. R. (1988). Phase space electroencephalography (EEG): a new mode of intraoperative EEG analysis. International journal of clinical monitoring and computing, 5(1), 3-13.More infoIntraoperative monitoring of electroencephalography (EEG) data can help assess brain integrity and/or depth of anesthesia. We demonstrate a computer generated technique which provides a visually robust display of EEG data plotted as 'phase space trajectories' and a mathematically derived parameter ('dimensionality') which may correlate with depth of anesthesia. Application of nonlinear mathematical analysis, used to describe complex dynamical systems, can characterize 'phase space' EEG patterns by identifying attractors (geometrical patterns in phase space corresponding to specific ordered EEG data subjects) and by quantifying the degree of order and chaos (calculation of dimensionality). Dimensionality calculations describe the degree of complexity in a signal and may generate a clinically useful univariate EEG descriptor of anesthetic depth. In this paper we describe and demonstrate phase space trajectories generated for sine waves, mixtures of sine waves, and white noise (random chaotic events). We also present EEG phase space trajectories and dimensionality calculations from a patient undergoing surgery and general anesthesia in 3 recognizable states: awake, anesthetized, and burst suppression. Phase space trajectories of the three states are visually distinguishable, and dimensionality calculations indicate that EEG progresses from 'chaos' (awake) to progressively more 'ordered' attractors (anesthetized and burst suppression).
- Calkins, J. M., Waterson, C. K., Quan, S. F., Militzer, H. W., Otto, C. W., Conahan, T. J., & Hameroff, S. R. (1987). Effect of alterations in frequency, inspiratory time, and airway pressure on gas exchange during high frequency jet ventilation in dogs with normal lungs. Resuscitation, 15(2), 87-96.More infoHigh frequency jet ventilation (HFJV) is becoming increasingly useful for providing respiratory support in patients with normal lungs during operative procedures, and also has been advocated as a technique for ventilating patients during cardiopulmonary resuscitation. We studied the effect of frequency, percent inspiratory time (I/E ratio), peak airway pressure, and airway pressure difference (peak-PEEP) during HFJV as operational variables on the efficacy of gas exchange in dogs with normal lungs. We observed that at a constant peak airway pressure and percent inspiratory time, PaCO2 generally increases as frequency rises above 100/min. In contrast, PaCO2 generally decreases as percent inspiratory time is reduced at a constant frequency and peak airway pressure. In addition, increasing peak airway pressure and airway pressure difference are associated with lower levels of PaCO2. Arterial oxygenation was adversely affected by frequencies above 300/min, but was otherwise not influenced by alterations in frequency, percent inspiratory time, or airway pressure.
- Pierce, P. A., Mylrea, K. C., Watt, R. C., Hameroff, S. R., Cork, R. V., & Calkins, J. M. (1986). Effects of pulse duration on neuromuscular blockade monitoring: implications for supramaximal stimulation. Journal of clinical monitoring, 2(3), 169-73.More infoQuestions have been raised concerning the reliability of surface electrodes in achieving supramaximal stimulation during the monitoring of neuromuscular blockade; needle electrodes are considered reliable in this respect. This study compares interelectrode impedances of needle and surface electrodes during neuromuscular blockade monitoring and suggests those characteristics of the stimulation pulse that can ensure reliable supramaximal stimulation with either type of electrode. Interelectrode voltage and current for surface and needle electrodes were measured by using 1.0-ms pulses at low, medium, and high stimulation levels on 22 surgical patients during anesthesia. Data were collected immediately after electrode application, and again at 10 minutes after application. Stimulation with surface electrodes produced an initial, transient surge of current, followed by a lower steady-state value. At high stimulation levels, the peak transient current was 87% higher than the steady-state current. Needle electrodes produced a constant high-current response. At high stimulation levels the transient impedance of the surface electrode and the impedance of the needle electrode were essentially equal (0.7 k omega and 0.75 k omega, respectively). The transient impedance was significantly lower (P less than 0.001) and was associated with less interpatient variation (P less than 0.001) and less sensitivity to the duration of electrode application than was the steady-state impedance of the surface electrode. These data suggest that high-current pulses with widths of less than 0.2 ms could provide reliable supramaximal stimulation with either type of electrode.
- Weinstein, P. R., Hameroff, S. R., Johnson, P. C., & Anderson, G. G. (1986). Effect of hyperbaric oxygen therapy or dimethyl sulfoxide on cerebral ischemia in unanesthetized gerbils. Neurosurgery, 18(5), 528-32.More infoTo determine whether treatment with hyperbaric oxygen (HBO) or dimethyl sulfoxide (DMSO) could mitigate the fatal effects of cerebral ischemia, we anesthetized 68 gerbils with ketamine, ligated the right carotid artery (CA), and placed a snare occluder around the left CA. After 48 hours, 30 gerbils that were neurologically normal or had suffered only mild deficits were subjected to left CA occlusion without anesthesia for periods of 2 to 60 minutes. The onset of circling, posturing, falling, and lethargy began immediately; seizures and coma ensued 4 to 5 minutes later and persisted until release of the left CA occluder. All gerbils recovered after 2-minute staged bilateral CA occlusions. The mortality rate was 33% after both 5- and 10-minute occlusions and 100% after 20- and 60-minute bilateral occlusions. Twelve gerbils were placed in an HBO chamber (100% oxygen at 1.5 atmospheres) for 15 minutes during 20-minute bilateral occlusion; only 2 died (16% mortality rate). Thus, HBO therapy conferred significant protection against death from untreated ischemia (P less than 0.001). Histological examination showed that the extent of patchy bilateral ischemic neuronal damage was much less in surviving gerbils that received HBO therapy than in those that died after 20-minute occlusions. Fourteen gerbils were treated with DMSO, 2.5 g/kg intraperitoneally, during 5- or 10-minute bilateral CA occlusion; 12 died (86% mortality rate). Thus, DMSO provided no protection against fatal cerebral infarction; in fact, the results in the 10-minute reperfusion group suggest that DMSO may have a deleterious effect.
- Cork, R. C., Hameroff, S. R., & Weiss, J. L. (1985). Effects of halothane and fentanyl anesthesia on plasma beta-endorphin immunoreactivity during cardiac surgery. Anesthesia and analgesia, 64(7), 677-80.More infoWe studied the effects of halothane anesthesia (n = 6) and fentanyl anesthesia (n = 9; 50-100 micrograms/kg) on plasma beta-endorphin immunoreactivity as a measure of stress response during coronary artery bypass grafting, including cardiopulmonary bypass. Plasma levels of beta-endorphin immunoreactivity measured prior to induction, after induction, after intubation, after skin incision, during cardiopulmonary bypass, and on leaving the operating room were significantly higher in patients given halothane during cardiopulmonary bypass and on leaving the operating room than they were in patients given fentanyl.
- Misiaszek, J., Cork, R. C., Hameroff, S. R., Finley, J., & Weiss, J. L. (1984). The effect of electroconvulsive therapy on plasma beta-endorphin. Biological psychiatry, 19(3), 451-5.
- Mylrea, K. C., Hameroff, S. R., Calkins, J. M., Blitt, C. D., & Humphrey, L. L. (1984). Evaluation of peripheral nerve stimulators and relationship to possible errors in assessing neuromuscular blockade. Anesthesiology, 60(5), 464-6.More infoVoltage and current output characteristics were measured on six commercially available peripheral nerve stimulator devices. The results are evaluated as possible sources of variability in peripheral nerve stimulator function and neuromuscular blockade assessment. The authors found significant differences in output voltage waveform and in maximum current into a 470 ohm load (21.4 to 128 mA.). Output current decreased from 25 to 88% in the different devices, with a load impedance increase from 470 to 10,000 ohms. Due to the variability in peripheral nerve stimulation units and the decrease in current output at higher load impedance, less than supramaximal stimulation is possible with erroneous interpretation of neuromuscular blockade.
- Otto, C. W., Quan, S. F., Conahan, T. J., Calkins, J. M., Waterson, C. K., & Hameroff, S. R. (1983). Hemodynamic effects of high-frequency jet ventilation. Anesthesia and analgesia, 62(3), 298-304.More infoThe hemodynamic effects of high-frequency jet ventilation (HFJV) and conventional ventilation were compared in normovolemic and functionally hypovolemic dogs. In normovolemic animals, no differences in hemodynamic function were found among spontaneous ventilation, conventional ventilation, and HFJV. When venous return was impaired by 15 cm H2O PEEP, cardiac index and stroke index were 25% higher with HFJV than with conventional ventilation (P less than 0.05). In another study with PEEP, conventional ventilation was compared to spontaneous ventilation, HFJV synchronized to five different parts of the cardiac cycle, and asynchronous HFJV. Heart rate was 15% lower and mean arterial pressure was 26% lower with conventional ventilation than with HFJV modes (P less than 0.05). There were no differences between synchronous and asynchronous HFJV. These results indicate that hemodynamic dysfunction may be less likely with HFJV than conventional ventilation. No advantage of synchronizing jet pulsations to a specific part of the cardiac cycle could be demonstrated.
- Calkins, J. M., Waterson, C. K., Hameroff, S. R., & Kanel, J. (1982). Jet pulse characteristics for high-frequency jet ventilation in dogs. Anesthesia and analgesia, 61(3), 293-300.
- Blitt, C. D., Carlson, G. L., Rolling, G. D., Hameroff, S. R., & Otto, C. W. (1981). A comparative evaluation of pretreatment with nondepolarizing neuromuscular blockers prior to the administration of succinylcholine. Anesthesiology, 55(6), 687-9.
- Stiffel, P., Hameroff, S. R., Blitt, C. D., & Cork, R. C. (1980). Variability in assessment of neuromuscular blockade. Anesthesiology, 52(5), 436-7.
- Chvapil, M., Hameroff, S. R., O'Dea, K., & Peacock, E. E. (1979). Local anesthetics and wound healing. The Journal of surgical research, 27(6), 367-71.
- Shanfield, S. B., Hameroff, S. R., Boyer, J. T., & Cox, S. S. (1979). Clinical aspects of pain. Part II. Arizona medicine, 36(8), 585-7.
- Hameroff, S. R. (2019, January 2019). Quantum approaches to consciousness.. Consciousness in Science Conference. University of Florida Gainsville, FL.
- Hameroff, S. R. (2019, January/Spring). Consciousness in the Universe. Consciousness in Science. University of Florida, Gainsville, FL: Bhaktivedanta Institute and University of Florida.
- Hameroff, S. R. (2019, July/Summer). Keynote Talk: Quantum approach to health and disease. Quantum Activism Conference. Bologna, Italy.
- Hameroff, S. R. (2019, July/Summer). Plenary Talk, Consciousness in the Universe. Science and Nonduality conference. Titignano Castle, Ovieto, Italy.
- Hameroff, S. R. (2019, June 2019). 'Quantum biology - State of the Debate', Quantum Biology Workshop. The Science of Consciousness.
- Hameroff, S. R. (2019, June/Summer). Plenary talk. The Science of Consciousness. Tucson, AZ.
- Hameroff, S. R. (2019, September/Fall). Plenary Talk 'Anesthetic action supports the Penrose-Hameroff Orch OR theory of consciousness. Models of Consciousness. Oxford, UK.
- Hameroff, S. R. (2016, October). Polar and Non-polar (quantum) regulation of coherent protein dynamics. Conference on the Physics, Chemistry and Biology of Water. Sofia, Bulgaria.
- Hameroff, S. R. (2016, October). The 'Meyer-Overton Correlation' explains quantum biology and the origin of consciousness. 10th Biennial European Conference of the Society for Scientific Exploration. Sigtuna, Sweden.
- Dayhoff, J., Hameroff, S. R., Lahoz-Beltra, R., & Swenberg, C. (1992, June). Intracellular mechanisms in neuronal learning: adaptive models. Neural Networks.. International Joint Conference on Neural Networks..
- Dayhoff, J., Hameroff, S. R., Swenberg, C., Lahoz-Beltra, R., & Sarnsonovich, A. (1992, June). Biological learning with cytoskeletal signaling Neural Networks. international Joint Conference on Neural Networks.
- Hameroff, S. R., Dayhoff, J., & Koruga, D. (1992, October). Cytoskeletal conformational automata: intra-neuronal support of neural networks.. Institute of Electrical and Electronics Engineers International Conference.
- Rasmussen, S., Karampurwala, H., Vaidyanath, R., & Hameroff, S. R. (1989, November). Emergent computation in microtubule model networks. Engineering in Medicine and Biology Society. Images of the Twenty First Century.. Proceedings of the Annual International Conference of the Institute of Electrical and Electronics Engineers.
- Watt, R., Ehlers, K., Scipione, P., Maslana, E., & Hameroff, S. R. (1989, November). Dimensional analysis of the electroencephalogram during general anesthesia. Engineering in Medicine and Biology Society, 1989. Images of the Twenty First Century,. Proceedings of the Annual International Conference of the Institute of Electrical and Electronics Engineers..
- Hameroff, S. R., Watt, R., Suwarno, N., Maslana, E., Mylrea, K., & Scipione, P. (1988, November). Esophageal contractility monitoring for anesthetic depth assessment. Engineering in Medicine and Biology Society, 1988.. Proceedings for the Annual International Conference of the Institute of Electrical and Electronics Engineers.
- Simic-Krstic, Y., Kelley, M., Schneiker, C., Krasovich, M., McCuskey, R., Koruga, D., & Hameroff, S. R. (1988, November). EEG monitoring for anesthetic depth assessment, Engineering in Medicine and Biology Society. Proceedings of the Annual International Conference of the Institute of Electrical and Electronics Engineers.
- Hameroff, S. R. (2018. Bioessays.
- Hameroff, S. R. (2017. Anesthesia and Analgesia.
- Hameroff, S. R. (2017. Medical Hypothesis.
- Hameroff, S. R. (2017. Physica A.
- Craddock, J., Hameroff, S. R., Ayoub, A., Klobukowski, M., & Tuszynski, J. (2015. Anesthetics act in quantum channels in brain microtubules to prevent consciousness.
- Craddock, J., Friesen, D., Mane, J., Hameroff, S. R., & Tuszynski, T. J. (2014. The Feasibility of Coherent Energy Transfer in Microtubules.
- Hameroff, S. R., Craddock, T., & Tuszynski, J. (2014. Quantum effects in the understanding of consciousness.
- Hameroff, S. R., & Penrose, R. (2011. Consciousness in the Universe: A review of the 'Orch OR' theory.
- Calkins, J. M., Waterson, C. K., Hameroff, S. R., Harris, T. R., & Jones, J. F. (1982. A simple flueric high frequency jet ventilator(pp 138-41).
- Bentley, J. B., & Hameroff, S. R. (1980. Diffuse reflex sympathetic dystrophy(pp 256-7).
- Reynolds, A. F., Hameroff, S. R., Blitt, C. D., & Roberts, W. L. (1980. Spinal subdural epiarachnoid hematoma: a complication of a novel epidural blood patch technique(pp 702-3).
- Hameroff, S. R. (2016, October). Panel Discussion: Different interpretations on David Bohm's ideas of quantum physics and consciousness.
- Craddock, J., Hameroff, S. R., Ayoub, A. b., Klobukowski, M., & Tuszynski, J. (2015, June). Anesthetics act in quantum channels in brain microtubules to prevent consciousness. Current Topics in Medicinal Chemistry.
- Hameroff, S. R. (2015, July). Is Your Brain Really a Computer, or Is It a Quantum Orchestra?. http://www.huffingtonpost.com/stuart-hameroff/is-your-brain-really-a-co_b_7756700.html
- Hameroff, S. R. (2015, June). Darwin Versus Deepak', Which came First, Feelings, or the Brain?. Huffington Post Blog. http://www.huffingtonpost.com/stuart-haameroff/darwin-versus-deepak-whic_b_7481048.html
- Hameroff, S. R. (2015, June). More Rational Than Thou. Huffington Post. http://www.huffingtonpost.com/stuart-hameroff/more-rational-than-thou-a_b_7515498.html
- Plezia, P. M., Kramer, T. H., Linford, J., & Hameroff, S. R. (1989). Transdermal fentanyl: pharmacokinetics and preliminary clinical evaluation. Pharmacotherapy.More infoA new transdermal drug-delivery system that administers the synthetic opioid fentanyl through intact skin was evaluated for 24 hours postoperatively in eight patients who had undergone orthopedic surgery. Plasma samples were obtained over a 72-hour period for pharmacokinetic analysis in five patients. The patients were also evaluated intensively for adequacy of analgesia, frequency of nausea and sedation, and occurrence of ventilatory depression. A median lag time of 2.25 hours after application of the transdermal system was observed before the appearance of fentanyl in the blood. Median peak concentration and time to peak were 1.0 ng/ml and 22 hours, respectively. The apparent elimination of fentanyl after transdermal administration is prolonged relative to previously reported values. Absorption analysis indicates zero-order fentanyl administration, and in addition, suggests deposition of drug in an epidermal site, with the resultant prolonged absorption process giving the appearance of slow elimination. No significant toxicities were observed. Four patients required no additional analgesia. No consistent correlations among fentanyl concentration and any clinical values were observed. Transdermal administration of fentanyl appears to be a viable alternative to conventional routes of narcotic administration and warrants further study.
- Cork, R. C., Weiss, J. L., Hameroff, S. R., & Bentley, J. (1984). Fentanyl preloading for rapid-sequence induction of anesthesia. Anesthesia and analgesia.More infoProtecting the patient's airway is of paramount importance in the induction of general anesthesia. For the patient at risk of regurgitation of stomach contents, the rapid-sequence (crash) induction provides protection, but at the expense of increased stress response to laryngoscopy and intubation. This stress response is especially dangerous for the patient at risk for myocardial ischemia. The purpose of this study was to examine the efficacy of using low-dose fentanyl (5 micrograms/kg) to reduce cardiovascular and neuroendocrine stress responses to rapid-sequence induction. Thirty patients were randomly assigned to a rapid-sequence induction protocol either with or without fentanyl preloading. Fentanyl-preloaded patients (fentanyl group) received 2 mg/kg of thiopental whereas patients who were not preloaded with fentanyl (control group) received 4 mg/kg of thiopental. Data collected as indices of the stress response included heart rate, systolic, diastolic, and mean blood pressures, and plasma concentrations of catecholamines (epinephrine, norepinephrine, dopamine) and beta-endorphin. Electrocardiograms (modified V5 lead) were monitored for dysrhythmias and ST segment depression. Control patients had higher systolic, diastolic, and mean blood pressures after intubation than did patients given fentanyl (P less than 0.05). Although the incidence of dysrhythmias was decreased by fentanyl (20% vs 42%), this difference was not statistically significant. Plasma concentrations of beta-endorphin and norepinephrine increased significantly in control patients but not in patients given fentanyl (P less than 0.05). Low-dose fentanyl (5 micrograms/kg) reduces some aspects of the stress response to rapid-sequence induction of anesthesia.
- Otto, C. W., Quan, S. F., Calkins, J. M., Waterson, C. K., & Hameroff, S. R. (1984). Mean airway pressure and hemodynamic effects. Anesthesiology.
- Stiffel, P., & Hameroff, S. R. (1979). A modified technique for transtracheal anesthesia. Anesthesiology.