Monash-led psilocybin study finds the brain reorganizes around context rather than simply becoming desynchronized

A Monash-led study of 62 psychedelic-naive adults finds that psilocybin does more than reduce within-network connectivity and brain modularity. Participants received a fixed 19 milligram dose and were scanned with fMRI and EEG while resting, meditating, listening to music, or watching a film. Although conventional averages supported the field's desynchronization account, time-resolved machine learning showed that brain activity remained able to identify each context above chance, suggesting stronger moment-to-moment alignment with what participants were doing. In a six-person network analysis, classification accuracy rose from about 62 percent at baseline to 98 percent under psilocybin, with the default mode and visual networks contributing substantially. This context alignment, termed embeddedness, correlated with self and boundary dissolution and with next-day mindset change, but not with anxiety or cognitive impairment. The open-label design, fixed condition order, healthy nonclinical sample, and small subgroup limit interpretation.