Key finding — 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.
Study at a glance
| Field | Detail |
|---|---|
| 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) |
| Journal | PNAS |
| Evidence | established |
Limitations
Small sample of experienced volunteers; fMRI measures are indirect proxies for neural activity, and intravenous dosing differs from oral use.
Editorial note
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. The confidence rating reflects our assessment of evidence strength.