Researchers Reveal Psychedelic Brain Patterns in Nature Study

A neuroscience team from Monash University studied how psilocybin affects human brain activity and found that psychedelic states show organized patterns alongside increased communication between brain regions, challenging the idea that the drug creates only random neural chaos.

The Nature study examined 62 people who had never used a psychedelic before. Researchers gave participants 19 milligrams of psilocybin, scanned their brains during the experience, and used artificial intelligence to analyze changes in brain activity.

The research team designed the PsiConnect experiment to capture uninterrupted psychedelic experiences. Participants completed four settings inside MRI and EEG scans: rest, guided meditation, curated music, and watching moving clouds.

The researchers avoided traditional cognitive tasks because they wanted to measure natural psychedelic experiences rather than responses interrupted by testing. About half of participants ranked their session among the most meaningful experiences of their lives, while 24 placed it among their top five.

Devon Stoliker, a neuroscientist at Monash University, said earlier explanations of psychedelic brain activity did not fully explain personal meaning or psychological effects.

"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," said Devon Stoliker, neuroscientist at Monash University.

Stoliker and his colleagues analyzed brain scans using machine learning to examine changes over time instead of relying only on traditional averages across scans and participants.

"Think of the networks of the brain as highways," said Devon Stoliker, neuroscientist at Monash University.

The team found that brain networks became less separated, with weaker connections inside individual networks and stronger links between different networks. Researchers also observed changes in how sensory and associative brain regions interacted.

"It seems like the brain’s ability to construct reality, or imagination, or our associations, our beliefs, our sense of self—these faculties had more dominance over sensory areas," said Devon Stoliker, neuroscientist at Monash University.

Stoliker described the interpretation as a hypothesis that could help explain complex imagery and personally meaningful experiences reported during psychedelic states.

"This could help explain why people have meaningful, complex imagery experiences, why they have mystical experiences with imagery that is personally relevant to them," said Devon Stoliker, neuroscientist at Monash University.

The EEG analysis supported the imaging results, showing that alpha-band activity, normally linked to filtering visual input, decreased by nearly half during the psychedelic experience.

"When somebody takes a psychedelic and they’re able to close their eyes and see complex imagery, there seems to be less boundary between the internal and external world than we ordinarily experience," said Devon Stoliker, neuroscientist at Monash University.

The researchers then used CEBRA, a machine learning tool, to map moment-by-moment activity from 332 brain regions while preserving the sequence of events.

"We wanted ecological validity," said Devon Stoliker, neuroscientist at Monash University.

"We wanted to know what the brain was like when somebody was having an authentic, uninterrupted psychedelic experience. If somebody took a psychedelic in a therapeutic setting, you wouldn’t have them completing tasks," said Devon Stoliker, neuroscientist at Monash University.

The analysis produced brain activity trajectories that separated into four clusters matching rest, meditation, music, and cloud-viewing periods. A classifier could identify the context from brain activity, and its accuracy increased with participants’ reported intensity of the experience.

"When they’re not under psilocybin, the brain activity is less differentiated by context," said Devon Stoliker, neuroscientist at Monash University.

"But under psilocybin, we see that the activity becomes organized across time and more clearly differentiated by context," said Devon Stoliker, neuroscientist at Monash University.