One of the most popular of my posts recently was about the beautiful visions that a peyote trip can bring. So you may also be interested to learn that a group of scientists have determined how psychedelics such as mescaline and LSD actually work in the brain (or so they theorize).
Singleton and his colleagues set out to test the so-called Rebus model of psychedelics. Standing for “relaxed beliefs under psychedelics”, it frames the brain as a prediction engine. Under the model, the brain takes thoughts and information from the senses and shapes them according to its understanding of the world. This makes the brain highly efficient: armed with prior beliefs, the noise and uncertainty of perception and thought are swiftly hammered into coherent reality.
But the brain works differently on psychedelics. According to Rebus, substances such as LSD weaken the influence of prior beliefs that the brain uses to make sense of the world. In one sense, the drugs rewind the brain’s clock to a time before it learned that walls tend not to move and furniture is rarely threatening.
“You can imagine you might experience altered perceptions,” said Amy Kuceyeski, a senior author on the study at Cornell. “If your prior belief is that walls don’t move and your prior belief melts, then that wall may appear to move…”
The ability of LSD to free up brain activity may explain why psychedelics can help people with depression, anxiety and other mental health disorders such as post-traumatic stress disorder. “In depression, people get locked into a way of thinking that is repetitive and ruminative. It’s like tramline thinking,” said Nutt. “Psychedelics disrupt those kinds of processes so people can escape from it.”