A hidden Markov model reliably characterizes ketamine-induced spectral dynamics in macaque local field potentials and human electroencephalograms
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.