Differential Effects of Propofol and Ketamine on Critical Brain Dynamics
bioRxiv Preprint Server March 27, 2020 Thomas F. Varley, Olaf Sporns, Aina Puce et al. 3 citations preprint
The brain may operate near a critical tipping point, a state thought necessary for consciousness and complex cognition. Using invasive ECoG recordings from a macaque transitioning between consciousness and unconsciousness under propofol and ketamine, the study found that propofol dramatically restricted the size and duration of neural avalanches and reduced the complexity of brain dynamics, while ketamine allowed more awake-like dynamics to persist. Despite these differences, all states showed some signs of persistent criticality when tested for exponent relations and universal shape-collapse, suggesting that maintenance of critical brain dynamics may be important for regulating conscious awareness.