Psychedelics like psilocybin alter consciousness by reorganizing brain connectivity in a context-sensitive way. In the largest psychedelic neuroimaging dataset to date, 62 adults underwent functional MRI and EEG before and after ingesting 19 mg of psilocybin, during rest and naturalistic stimuli. Under psilocybin, brain signals during eyes-closed conditions became similar to those during eyes-open conditions, with increased global functional connectivity in associative regions and decreased connectivity in sensory areas. Machine learning linked subjective effects to structured neural activity patterns. Stronger self-dissolving effects were associated with more distinct neural representations and next-day mindset changes, revealing a state of 'embeddedness' where networks that usually segregate internal and external processing integrate coherently, aligning neural dynamics with context.
PsiConnect is a large-scale neuroimaging study that examined brain activity in 62 participants before and after a 19 mg dose of psilocybin using functional, structural, and diffusion-weighted MRI combined with EEG. The design included resting-state scans and three naturalistic conditions: guided meditation, music listening, and movie watching. Half of the participants completed an 8-week meditation training program, allowing exploration of interactions among meditation, psilocybin, and brain function. Multi-echo fMRI improved signal-to-noise ratio and reduced artifacts. Behavioral and self-report measures captured acute and longitudinal effects, with follow-ups extending to one year. The data is curated according to open science principles.