Neuroimaging & Brain MeasuresHealthy VolunteersPsilocybin

Psilocybin desynchronizes brain networks

Using dense longitudinal fMRI mapping, a single high dose of psilocybin massively desynchronised cortical and subcortical functional connectivity—dissolving within-network correlations and between-network anticorrelations—far more than methylphenidate and with the strongest effect in the default mode network. These acute changes tracked subjective experience, were attenuated by a perceptual task, and included a persistent reduction in anterior hippocampus–DMN coupling lasting weeks that may underlie psilocybin’s proplasticity and therapeutic effects.

Authors

  • Nicol, G. E.

Published

Nature
individual Study

Abstract

A single dose of psilocybin, a psychedelic that acutely causes distortions of space–time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials 1–4 . In animal models, psilocybin induces neuroplasticity in cortex and hippocampus 5–8 . It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg), and brought back for an additional psilocybin dose 6–12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics.

Available with Blossom Pro

Research Summary of 'Psilocybin desynchronizes brain networks'

Introduction

Earlier research shows that a single high dose of psilocybin produces rapid, sometimes long-lasting therapeutic effects in humans and induces synaptogenesis and other plasticity-related changes in animal models. However, how macroscopic human brain networks change acutely and persistently after psychedelic exposure, and how those changes relate to subjective experiences such as ego dissolution or altered time/space perception, remains unclear. Previous human studies reported reduced network segregation, increased metabolic activity and altered electrophysiological power during the acute psychedelic state, but lacked the longitudinal, individual-specific resolution needed to link network dynamics to subjective effects and to persistent neuroplastic changes. This study set out to map individual-specific brain network changes before, during and after high-dose oral psilocybin using intensive longitudinal precision functional mapping. Siegel and colleagues compared psilocybin (25 mg) with an active stimulant control (40 mg methylphenidate, MTP), related functional connectivity (FC) changes to subjective psychedelic intensity (MEQ30), tested whether task engagement modulates those changes, quantified a measure of spatial desynchronization (NGSC) and examined whether any FC changes persist for up to three weeks and at a 6–12 month replication visit. The study therefore aimed to connect acute network-level effects, subjective experience and candidate persistent circuit-level changes that could plausibly underlie pro-plasticity and therapeutic mechanisms.

Expert Research Summaries

Go Pro to access AI-powered section-by-section summaries, editorial takes, and the full research toolkit.

Full Text PDF

Full Paper PDF

Pro members can view the original manuscript directly in the browser.

Study Details

  • Study Type
    individual
  • Journal
  • Compound
  • Topics
  • APA Citation

    Siegel, J. S., Subramanian, S., Perry, D., Kay, B. P., Gordon, E. M., Laumann, T. O., Reneau, T. R., Metcalf, N. V., Chacko, R. V., Gratton, C., Horan, C., Krimmel, S. R., Shimony, J. S., Schweiger, J. A., Wong, D. F., Bender, D. A., Scheidter, K. M., Whiting, F. I., Padawer-Curry, J. A., . . . Dosenbach, N. U. F. (2024). Psilocybin desynchronizes brain networks. Nature, 632(8023), 131-138. https://doi.org/10.1038/s41586-024-07624-5

References (34)

Papers cited by this study that are also in Blossom

Single-Dose Psilocybin for a Treatment-Resistant Episode of Major Depression

Goodwin, G. M., Aaronson, S. T., Alvarez, O. et al. · New England Journal of Medicine (2022)

656 cited
Single-Dose Psilocybin Treatment for Major Depressive Disorder: A Randomized Clinical Trial

Raison, C. L., Sanacora, G., Woolley, J. D. et al. · JAMA (2023)

375 cited
Trial of Psilocybin versus Escitalopram for Depression

Carhart-Harris, R. L., Giribaldi, B., Watts, R. et al. · New England Journal of Medicine (2021)

927 cited
A non-hallucinogenic psychedelic analogue with therapeutic potential

Cameron, L. P., Tombari, R. J., Lu, J. et al. · Nature (2020)

70 cited
Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action

Vollenweider, F. X., Vollenweider-Scherpenhuyzen, M. F. I., Bäbler, A. et al. · NeuroReport (1998)

Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study

Carhart-Harris, R. L., Bolstridge, M., Rucker, J. et al. · Lancet Psychiatry (2016)

1174 cited
The therapeutic potential of psychedelic drugs: past, present, and future

Carhart-Harris, R. L., Goodwin, G. M. · Neuropsychopharmacology (2017)

Psychedelics promote structural and functional neural plasticity

Ly, C., Greb, A. C., Cameron, L. P. et al. · Cell Reports (2018)

Show all 34 references
A Dendrite-Focused Framework for Understanding the Actions of Ketamine and Psychedelics

Savalia, N., Shao, L-X,, Kwan, A. C. · Trends in Neuroscience (2021)

98 cited
Broadband Cortical Desynchronization Underlies the Human Psychedelic State

Muthukumaraswamy, S. D., Carhart-Harris, R. L., Moran, R. J. et al. · Journal of Neuroscience (2013)

427 cited
Increased global functional connectivity correlates with LSD-induced ego dissolution

Tagliazucchi, E., Roseman, L., Kaelen, M. et al. · Current Biology (2016)

A complex systems perspective on psychedelic brain action

Girn, M., Rosas, F. E., Daws, R. E. et al. · Trends in Cognitive Sciences (2023)

Lasting effects of a single psilocybin dose on resting-state functional connectivity in healthy individuals

McCulloch, D. E-W., Madsen, M. K., Stenbæk, D. S. et al. · Journal of Psychopharmacology (2021)

Increased global integration in the brain after psilocybin therapy for depression

Daws, R. E., Timmermann, C., Giribaldi, B. et al. · Nature Medicine (2022)

Emotions and brain function are altered up to one month after a single high dose of psilocybin

Barrett, F. S., Doss, M. K., Sepeda, N. D. et al. · Scientific Reports (2020)

Prolonged ketamine infusion modulates limbic connectivity and induces sustained remission of treatment-resistant depression

Siegel, J. S., Palanca, B. J. A., Ances, B. M. et al. · Psychopharmacology (2021)

Validation of the revised Mystical Experience Questionnaire in experimental sessions with psilocybin

Barrett, F. S., Johnson, M. W., Griffiths, R. R. · Journal of Psychopharmacology (2015)

Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin

Carhart-Harris, R. L., Erritzoe, D., Williams, T. et al. · PNAS (2012)

Neural correlates of the LSD experience revealed by multimodal neuroimaging

Carhart-Harris, R. L., Muthukumaraswamy, S., Roseman, L. et al. · PNAS (2016)

Classical and non-classical psychedelic drugs induce common network changes in human cortex

Dai, R., Larkin, T. E., Huang, Z. et al. · NeuroImage (2023)

41 cited
Human hallucinogen research: guidelines for safety

Johnson, M. W., Richards, W. A., Griffiths, R. R. · Journal of Psychopharmacology (2008)

Effects of external stimulation on psychedelic state neurodynamics

Mediano, P. A. M., Rosas, F. E., Timmermann, C. et al. · ACS Chemical Neuroscience (2024)

Psychedelics reopen the social reward learning critical period

Nardou, R., Sawyer, E., Song, Y. J. et al. · Nature (2023)

The psychedelic state induced by ayahuasca modulates the activity and connectivity of the default mode network

Palhano-Fontes, F., Andrade, K. C., Tófoli, L.F. et al. · PLOS ONE (2015)

Neuroimaging in psychedelic drug development: Past, present, and future

Wall, M. B., Harding, R., Zafar, R. et al. · Molecular Psychiatry (2023)

Neural correlates of the DMT experience assessed with multivariate EEG

Timmermann, C., Roseman, L., Schartner, M. et al. · Scientific Reports (2019)

The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs

Carhart-Harris, R. L., Leech, R., Shanahan, M. et al. · Frontiers in Human Neuroscience (2014)

Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults

Brown, R. T., Nicholas, C. R., Cozzi, N. V. et al. · Clinical Pharmacokinetics (2017)

Cited By (8)

Papers in Blossom that reference this study

Psychedelic medicine: mechanisms, evidence, and translation to practice

Jacobs, E., Zahid, Z., Hinkle, J. et al. · BMJ (2026)

Psilocybin’s acute and persistent brain effects: a precision imaging drug trial

Subramanian, S., Renau, R., Perry, D. et al. · Scientific Data (2025)

2 cited
Psychedelics Align Brain Activity with Context

Stoliker, D., Novelli, L., Khajehnejad, M. et al. · Biorxiv (2025)

Brain substates induced by DMT relate to sympathetic output and meaningfulness of the experience

Pasquini, L., Simon, A. J., Gallen, C. L. et al. · Biorxiv (2024)

4 cited
20 cited

Your Personal Research Library

Go Pro to save papers, add notes, rate studies, and organize your research into custom shelves.