Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin

This experiment measured brain states (fMRI) under psilocybin infusion, and found more general coherence (communication) and lower frontoparietal network activity.

This paper used the same methods (but new participants) as ‘Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin‘ (Carhart-Harris et al, 2012).

Abstract of Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin

“Growing evidence from the dynamical analysis of functional neuroimaging data suggests that brain function can be understood as the exploration of a repertoire of metastable connectivity patterns (‘functional brain networks’), which potentially underlie different mental processes. The present study characterizes how the brain’s dynamical exploration of resting-state networks is rapidly modulated by intravenous infusion of psilocybin, a tryptamine psychedelic found in “magic mushrooms”. We employed a data-driven approach to characterize recurrent functional connectivity patterns by focusing on the leading eigenvector of BOLD phase coherence at single-TR resolution. Recurrent BOLD phase-locking patterns (PL states) were assessed and statistically compared pre- and post-infusion of psilocybin in terms of their probability of occurrence and transition profiles. Results were validated using a placebo session. Recurrent BOLD PL states revealed high spatial overlap with canonical resting-state networks. Notably, a PL state forming a frontoparietal subsystem was strongly destabilized after psilocybin injection, with a concomitant increase in the probability of occurrence of another PL state characterized by global BOLD phase coherence. These findings provide evidence of network-specific neuromodulation by psilocybin and represent one of the first attempts at bridging molecular pharmacodynamics and whole-brain network dynamics.“

Authors: Louis-David Lord, Paul Expert, Selen Atasoy, Leor Roseman, Kristina Rapuano, Renaud Lambiotte, David J. Nutt, Gustavo Deco, Robin L. Carhart-Harris, Morten L. Kringelbach & Joana Cabral

Summary of Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin

Brain dynamics can be understood as the exploration of activity configurations over both space and time, and may be related to cognitive function. Although the mechanisms driving the spontaneous formation and dissolution of functional networks remain under debate, recent evidence suggests that transitions between brain states are organized in a hierarchical manner.

Psilocybin, a prodrug of psilocin, changes the exploration of the brain’s dynamical repertoire, leading to broad unconstrained perception and cognition, hyper-associative cognition, and a breakdown in the perception of time, space and selfhood. Psilocybin has potent psychoactive effects due to its agonist activity at the serotonin 2A (5-HT2A) receptor, and it may help understand the functional mechanisms underlying the recently demonstrated therapeutic potential of psilocybin for disorders including depression, anxiety and addiction.

Psilocybin increases the variance of intra-network synchrony over time, and increases the entropy of the motif sequence in a specific network of four brain regions. However, an increase in local complexity does not necessarily imply higher randomness at the larger scale. The serotonergic psychedelics psilocybin and LSD induce a different type of functional integration, characterized by greater global integration, but this has not yet been explored.

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Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin

https://doi.org/10.1016/j.neuroimage.2019.05.060

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Cite this paper (APA)

Lord, L. D., Expert, P., Atasoy, S., Roseman, L., Rapuano, K., Lambiotte, R., ... & Cabral, J. (2019). Dynamical exploration of the repertoire of brain networks at rest is modulated by psilocybin. NeuroImage, 199, 127-142.

Study details

Compounds studied
Psilocybin

Topics studied
Neuroscience

Study characteristics
Theory Building Bio/Neuro

Participants
9 Humans

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