bioRxiv (Cold Spring Harbor Laboratory)
March 11, 2025
Devon Stoliker, Leonardo Novelli, Moein Khajehnejad et al.
8 citations
preprint
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.
bioRxiv (Cold Spring Harbor Laboratory)
April 14, 2025
Leonardo Novelli, Devon Stoliker, Tamrin Barta et al.
3 citations
preprint
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.
bioRxiv (Cold Spring Harbor Laboratory)
August 22, 2025
Matthew D. Greaves, Tamrin Barta, Leonardo Novelli et al.
preprint
Psilocybin reorganizes directed influences between brain regions while preserving the underlying structural connectivity, according to fMRI data analyzed with a dynamic causal model. Across four contexts—rest, guided meditation, music listening, and movie viewing—effects converged on outgoing influences from the left hippocampus, a hub linking memory and association systems with the default-mode network and thalamus. The left-hippocampus-to-thalamus pathway showed a sign-reversed association with mystical-experience scores: downregulation during guided meditation and upregulation during music listening. Left-hippocampal efferents predicted individual differences in mystical-experience intensity in cross-validation, and a simpler measure of hippocampal signal variability showed modest associations.