" In the current study, the team used functional magnetic resonance imaging (fMRI) to scan the brain activity of 15 healthy volunteers — once after they had taken a placebo, and once after they took the hallucinogen psilocybin. (The team chose only people who had reported past positive experiences with magic mushrooms to prevent them from panicking inside the claustrophobic MRI machines.)
The team then compared the brain activity of the individuals on and off the drug, and created a map of connections between different brain regions.
"Psilocybin dramatically transformed the participants' brain organization, Expert said. With the drug, normally unconnected brain regions showed brain activity that was synchronized tightly in time. That suggested the drug was stimulating long-range connections the brain normally wouldn't make. After the drug wore off, brain activity went back to normal."