"In addition, recent neuroimaging studies of people under the influence of psychedelic drugs have shown that the elaborate mystical experiences associated with these drugs are accompanied by 'decreased' brain activity. This is the exact opposite of what we had expected. Traditional neuroscientific explanations of psychedelic drug trips assumed that psychedelic drugs like LSD and psilocybin increase brain activity, triggering hallucinations. But it appears that they instead decrease brain activity, particularly in the prefrontal cortex, and also sharply decrease the kind of synchronised electrical activity in the brain that is typically seen with complex thinking. This decrease in brain activity might reduce the brain's ability to filter the mind and permit access to mystical experiences. This is consistent with spiritual traditions from around the world that use choking, breath-holding, starvation, and extended sensory deprivation to induce mystical experiences."
After, Dr. Bruce Greyson [pag 191]
