Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin
Psilocybin decreased activity and connectivity in key hub regions of the brain, particularly the default mode network — a counterintuitive finding suggesting the psychedelic state involves reduced, not increased, activity in certain control centers.
- Institution
- Imperial College London
- Design
- Within-subject, placebo-controlled neuroimaging study
- Sample size
- 30 participants
- Intervention
- Intravenous psilocybin during functional MRI scanning
- Year
- 2012
- Condition
- Healthy volunteers (brain imaging)
Small sample of experienced volunteers; fMRI measures are indirect proxies for neural activity, and intravenous dosing differs from oral use.
The imaging study that introduced the influential idea that psychedelics quiet the brain’s default mode network. It anchored a decade of subsequent theory, including the entropic brain and REBUS models.
Summary written by MMI Editorial for clarity. Always consult the primary source for full methodology and results. Confidence rating reflects our assessment of evidence strength.