Altered subjective experience after psilocybin intake associates with a dynamic pattern of hyperconnected functional connectivity

To provide insights into the neurophenomenological richness after psilocybin intake, we investigated the link between brain dynamics and the ensuing alterations of reported experience. Healthy participants received either psilocybin (n=22) or placebo (n=27) while in ultra-high field 7T MRI scanning. Experiential changes were quantified using the 5-Dimensions of Altered States of Consciousness (5D-ASC) questionnaire, revealing alterations across all dimensions. Neuronally, psilocybin induced widespread increases in averaged functional connectivity. Time-varying analysis unveiled a recurrent hyperconnected pattern characterized by low BOLD signal amplitude, suggestive of heightened cortical arousal. Canonical correlation analysis linked the transition probabilities to this hyperconnected pattern with oceanic boundlessness and visionary restructuralization. We suggest that the brain’s tendency to enter a hyperconnected-hyperarousal pattern under psilocybin may represent the potential to entertain variant mental associations in a creative way. For the first time these findings link brain dynamics with subjective alterations, providing new insights into the neurophenomenology of altered states of consciousness. ### Competing Interest Statement The authors have declared no competing interest.