In mice and one person, scientists were able to reproduce the altered state often associated with ketamine by inducing certain brain cells to fire together in a slow-rhythmic fashion. “There was a rhythm that appeared and it was an oscillation that appeared only when the patient was dissociating,” says Dr. Karl Deisseroth, a psychiatrist and neuroscientist at Stanford University. https://sci-hub.tw/10.1038/s41586-020-2731-9
(via https://www.npr.org/sections/health-shots/2020/09/16/913565163/scientists-discover-way-to-induce-altered-state-of-mind-without-drugs?t=1600326978763)