By comparing scans of the brain on LSD versus placebo… researchers found that the drug reduced the amount of energy the brain needed to switch from one brain state another. [Researcher Dr. Amy] Kuceyeski likens it to flattening the landscape over which the brain can roam. Normally, the brain’s activity is constrained by the mountains and valleys of our prior beliefs, but on LSD these obstacles are flattened out. “It allows us to move more freely and have more dynamic brain activity,” she said.
“Under psychedelics, you go back to a state where bits of the brain that haven’t spoken since you were a baby can cross-talk. And it’s that increased connectivity that allows people to get new insights into old problems,” [neuropsychopharmacologist David Nutt] said.
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 [neuropsychopharmacologist David] Nutt. “Psychedelics disrupt those kinds of processes so people can escape from it.”