Taking psilocybin, the hallucinogenic compound found in magic mushrooms, temporarily resets entire networks of neurons in the brain that are responsible for controlling a person’s sense of time and self, finds a study that repeatedly imaged the brains of seven volunteers before, during and after they took a massive dose of the drug.

Psilocybin is one of several psychedelic drugs, including LSD, ketamine and MDMA (also known as ecstasy), that are being investigated as therapies for conditions such as depression and post-traumatic stress disorder. Despite promising data that have sped treatments towards approval, researchers still don’t fully understand the mechanism that underlies their therapeutic effects.

Mathur cautions that these data cannot show what precisely causes the potential therapeutic benefit of psilocybin — but they offer tantalizing clues. “It’s possible psilocybin is directly causing” the brain-network changes, he says — or perhaps it is creating a psychedelic experience that in turn causes parts of the brain to behave differently, he says.

This heat map shows how patterns of resting brain activity (blue and green) change when psilocybin is taken (red and yellow), then return to normal as the drug wears off. Credit: Sara Moser/Washington University