Neuroscientists at the University of Sussex recorded an increase in neural signal diversity in the brains of people using psychedelic drugs.
Previous studies have documented the increase in neural signal diversity levels in “aware and awake” brains, as compared to levels in sleeping brains — confirming the index as useful proxy for differing levels of consciousness.
The latest study, published in the journal Scientific Reports, is the first to show levels above baseline.
“This finding shows that the brain-on-psychedelics behaves very differently from normal,” Anil Seth, co-director of the Sackler Centre for Consciousness Science, said in a news release. “During the psychedelic state, the electrical activity of the brain is less predictable and less ‘integrated’ than during normal conscious wakefulness — as measured by ‘global signal diversity.’”
Researchers used brain imaging technology to measure electrical activity in the brains of people under the influence of psilocybin, ketamine and LSD. All three drugs induced higher levels of neural signal diversity.
“Since this measure has already shown its value as a measure of ‘conscious level,’ we can say that the psychedelic state appears as a higher ‘level’ of consciousness than normal — but only with respect to this specific mathematical measure,” Seth said.
The controlled use of psychedelics for medicinal purposes, such as treatment for depression, has been gaining momentum. The latest research can help scientists better understand how these drugs impact the human brain, and how they might be harnessed to treat mental health problems.
“The present study’s findings help us understand what happens in people’s brains when they experience an expansion of their consciousness under psychedelics,” said Robin Cahart-Harris, a neuroscientist at Imperial College London. “People often say they experience insight under these drugs — and when this occurs in a therapeutic context, it can predict positive outcomes. The present findings may help us understand how this can happen.” [….]