Subanaesthetic ketamine and altered states of consciousness in humans
British Journal of Anaesthesia April 13, 2018 Phillip E. Vlisides, Tarik Bel‐bahar, Amanda Nelson et al. 117 citations
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Vijay Tarnal
Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States.
6 papers in the library · 185 citations · publishing 2018-2026
Papers
Classical and non-classical psychedelic drugs induce common network changes in human cortex.
NeuroImage June 1, 2023 Rui Dai, Tony E Larkin, Zirui Huang et al. 49 citations
Three different psychedelics—nitrous oxide, ketamine, and lysergic acid diethylamide—produce a common pattern of brain network changes despite having distinct molecular mechanisms and delivery methods. Each drug reduced connectivity within brain networks and enhanced connectivity between networks. Specifically, all three increased connections between the right temporoparietal junction and bilateral intraparietal sulcus, and between the precuneus and left intraparietal sulcus. These regions lie within the posterior cortical "hot zone," an area thought to mediate the qualitative aspects of experience. The findings identify a biologically plausible candidate for the subjective effects of both classical and non-classical psychedelics.
Preliminary safety and effectiveness of psilocybin-assisted therapy in adults with fibromyalgia: an open-label pilot clinical trial
Frontiers in Pain Research March 18, 2025 Jenna McAfee, Avinash Hosanagar, Vijay Tarnal et al. 18 citations
In a small open-label pilot trial, five people with fibromyalgia received two doses of psilocybin (15 mg and 25 mg) along with psychotherapy. The treatment was well-tolerated: there were temporary increases in blood pressure or heart rate during dosing that returned to normal, no serious adverse events, and four of five participants had short-lived headaches. One month after the second dose, participants reported large reductions in pain severity, pain interference, and sleep disturbance. One participant rated their symptoms as very much improved, two as much improved, and two as minimally improved. Recruitment stopped early due to generalizability concerns and changing FDA guidance, but the results suggest psilocybin-assisted therapy is safe for fibromyalgia and warrants larger trials.
General Anesthesia and Discrete Components of Ketamine Neurophysiology.
JAMA psychiatry June 1, 2026 Ben Deverett, Duan Li, Theresa R Lii et al. 1 citation
Ketamine produces distinct brain-wave patterns that may be linked to its therapeutic effects. General anesthesia selectively blocks one of these patterns—theta oscillations—while leaving another pattern, beta-gamma oscillations, intact. In 52 participants, ketamine given during anesthesia preserved beta-gamma power increases but eliminated the characteristic theta augmentation seen during awake administration. This suggests that different neurophysiologic effects of ketamine can be separated, offering a way to investigate which brain-wave changes underlie its antidepressant, analgesic, or dissociative properties.
General anesthesia dissociates discrete components of ketamine neurophysiology
medRxiv August 7, 2025 Ben Deverett, Duan Li, Theresa R. Lii et al. preprint
Ketamine produces dissociative, analgesic, and antidepressant effects, but it is unclear whether its underlying neurophysiological signatures can be separated. In this observational cohort study, 52 participants (healthy volunteers, elective surgery patients, and patients with depression) received a subanesthetic infusion of ketamine or placebo, with or without general anesthesia. When ketamine was given under general anesthesia, its characteristic low-frequency brain wave augmentation was absent, while high-frequency power modulation was preserved. This selective modulation suggests a method for investigating the distinct roles of high- and low-frequency neural activity in ketamine's behavioral effects.
Preliminary safety and effectiveness of psilocybin-assisted therapy in adults with fibromyalgia: An open-label, pilot clinical trial
November 4, 2024 Jacob S. Aday, Jenna McAfee, Deirdre A. Conroy et al. preprint
In a small open-label proof-of-concept trial, five adults with fibromyalgia received two doses of psilocybin (15 mg and 25 mg) two weeks apart, along with psychotherapy sessions. No serious adverse events occurred; transient blood pressure or heart rate elevations during dosing resolved by the end of treatment, and four of five participants had temporary headaches. One month after the second dose, participants reported clinically meaningful improvements in pain severity, pain interference, and sleep disturbance. One participant rated their symptoms as very much improved, two as much improved, and two as minimally improved. Improvements were also seen in fibromyalgia symptoms, anxiety, and fatigue. The findings suggest psilocybin-assisted therapy is well-tolerated and warrants larger randomized controlled trials.