Anesthesiology
September 4, 2020
Jacob Gitlin, Shubham Chamadia, J. Locascio et al.
48 citations
Ketamine's pain-relieving effects are not solely due to its dissociative properties. In an open-label study, 15 healthy adults received 2 mg/kg of ketamine, with midazolam given later to reduce dissociation. Statistical models showed that dissociation and pain intensity followed similar time courses, but when dissociation scores were added to the pain model, dissociation did not account for the pain relief. This indicates that ketamine's analgesic and dissociative effects are independent, suggesting ketamine can be used to study pain circuits separate from those involved in dissociation.
PLoS Computational Biology
August 18, 2021
Indie C. Garwood, S. Chakravarty, Jacob Donoghue et al.
32 citations
Ketamine, an anesthetic that blocks NMDA receptors, produces alternating bursts of gamma (25-50 Hz) and slow-delta (0.1-4 Hz) brain oscillations. A hidden Markov model fitted to local field potentials from two non-human primates and electroencephalograms from nine humans quantified these dynamics. Gamma activity lasted on average 2.2 seconds in one primate, 1.2 in the other, and 2.5 in humans; slow-delta lasted 1.6, 1.0, and 1.8 seconds respectively. Five sub-states with regular sequential transitions were identified. These findings provide quantitative constraints for models of rhythm generation underlying ketamine-induced altered arousal.
PAIN Reports
June 3, 2021
Eunice Y. Hahm, Shubham Chamadia, J. Locascio et al.
6 citations
Ketamine given during general anesthesia reduces pain intensity by 3 points and increases dissociation scores by 17.8 points, but these two effects are independent: the pain reduction does not depend on dissociation. This suggests that ketamine's analgesic and dissociative properties involve separate brain circuits, even under general anesthesia, and that ketamine might be developed into a more targeted pain treatment without causing dissociation.
medRxiv Preprint Server
November 12, 2020
Indie C. Garwood, Sourish Chakravarty, Jacob Donoghue et al.
preprint
Ketamine, an anesthetic and psychoactive drug, produces alternating patterns of brain activity: bursts of gamma oscillations (30-50 Hz) and slow oscillations (0.1-10 Hz). A hidden Markov model (HMM) was applied to brainwave data from two non-human primates and nine human subjects receiving anesthetic doses of ketamine. The model revealed distinct states corresponding to gamma bursts and slow oscillations, with intermediate states. Mean gamma burst durations were 2.5 seconds (non-human primate 1), 1.2 seconds (non-human primate 2), and 2.7 seconds (humans). Mean slow oscillation durations were 1.6 seconds, 0.7 seconds, and 2.8 seconds, respectively. This framework provides quantitative constraints for understanding how ketamine alters states of consciousness.