Key facts
- Psychedelics do not cause pure chaos in the brain, but rather a hidden order.
- Brain networks under psilocybin become less distinct, with stronger connections between networks.
- AI analysis of brain scans showed that activity became organized across time and differentiated by context.
- The default mode network and visual network accounted for over 20% of the effect in organizing brain activity.
- Participants reported meaningful experiences, with half ranking their session among the most meaningful of their lives.
A recent study published in Nature challenges the long-held view that psychedelics induce pure chaos in the brain. Neuroscientist Devon Stoliker and his team at Monash University conducted an experiment with 62 participants who had no prior psychedelic experience. After administering 19 milligrams of psilocybin, the researchers used MRI and EEG scans, along with AI analysis, to observe brain activity.
Instead of finding random chaos, the study revealed a more nuanced picture. While brain networks, which are stable patterns of communication, did loosen and show increased cross-network communication, the overall activity became more organized and context-dependent. This suggests that the brain's ability to construct reality, imagination, and associations may gain dominance over sensory areas, potentially explaining the meaningful and insightful experiences reported by users.
The researchers employed a machine-learning tool called CEBRA to analyze moment-by-moment brain activity, creating trajectories that separated into distinct clusters corresponding to different contexts like rest, meditation, music, and watching clouds. The performance of a classifier trained on this data correlated with how profound participants described their experience.
Key brain regions involved in this organized activity included the default mode network, associated with the sense of self, and the visual network. The study posits that the reduced differentiation between these networks under psilocybin may contribute to a subjective experience of the self and the external world becoming less separate, a state referred to as 'embeddedness'. The findings suggest that psychedelics may alter the organization of brain networks that maintain this separation.