Psilocybin Study Finds Order, Not Just Chaos, in Brain Scans

Sixty-two adults who had never taken a psychedelic drug received 19 milligrams of psilocybin and went into an MRI scanner about 80 minutes later, according to a study led by Monash University neuroscientist Devon Stoliker and reported by Ars Technica. Half of the participants later ranked that session among the most meaningful experiences of their lives, and 24 of the 62 placed it in their personal top five, the outlet reported, citing the research team.

What did the study actually test?

The project, called PsiConnect, set out to check a decade-old assumption: that psychedelics simply scramble brain activity into noise. Each volunteer completed the same four-part sequence twice — once sober, once on psilocybin — covering eight minutes of rest, a guided meditation, an 11-minute music playlist, and six minutes of watching clouds move across the sky. Researchers skipped the cognitive tasks common in brain studies on purpose. "We wanted ecological validity," Stoliker told Ars Technica. "We wanted to know what the brain was like when somebody was having an authentic, uninterrupted psychedelic experience."

Why skip the usual lab tasks?

Stoliker said introducing tasks mid-trip can pull a subject out of the psychedelic state, a phenomenon researchers call grounding. Each person went through the sequence once in an MRI scanner roughly 80 minutes after dosing, then again under EEG about 150 minutes after dosing — giving the team two imaging methods across the same unscripted experience.

Did the scans show chaos or something else?

The team measured global functional connectivity, a gauge of how much influence each patch of the cortex exerts over the rest of the brain. With eyes closed, sensory regions lost influence while associative regions — the areas tied to memory, meaning, and self-referential thought — gained it. That pattern runs counter to the simple "everything talks to everything" chaos model. "Think of the networks of the brain as highways," Stoliker said. "Under psychedelics, these highways break down into many different directions" — but the redirection followed a structure rather than random noise.

Why does a reorganized brain matter for therapy?

Stoliker argued the chaos framing never explained the clinical reports coming out of psychedelic-assisted therapy trials. "It never really explained why an individual would have a meaningful experience, why they might have insight, why they might experience clarity, and why these might translate into positive psychological changes," he said. If associative regions gaining influence over sensory ones maps onto the insight and clarity patients describe, that gives researchers a measurable brain signature to study instead of relying solely on self-report surveys after a session.

What comes next for this research?

The published results, which appeared in Nature, cover one dose level — 19 milligrams — in a single-session design with no control for expectation effects beyond the sober/psilocybin comparison within the same subjects. Larger samples, different dosing, and replication outside Monash University's lab would be needed before the connectivity pattern can be treated as a reliable marker rather than a finding from one 62-person cohort. The original write-up is available via Ars Technica.