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03 · Mind and mechanism
What actually happens in the brain?
The Beckley/Imperial programme produced some of the most cited neuroimaging work in this field. The real finding is more interesting, and more counterintuitive, than the headline version.
Research from the Beckley/Imperial programme shows that psilocybin creates thousands of connections between brain regions that do not communicate with one another under normal conditions.2 At the same time, activity in the brain's central hub regions, including the medial prefrontal cortex and posterior cingulate cortex, falls.1
These two findings fit together. As the hubs that normally constrain how information travels become quieter, communication opens up across the wider system, producing a far more interconnected pattern than the brain shows at rest. Researchers associate this state with cognitive flexibility. Exactly how it connects to lasting change is still being worked out.
How this research relates to a Beckley retreat
The studies described here were run as clinical trials, in hospitals or research settings, using standardized synthetic compounds under medical supervision. Beckley is not a clinical program. Our retreats are non-clinical wellbeing experiences that use natural psilocybin and are built around preparation, a guided experience, and integration.
What the research found
Three findings from the Beckley/Imperial neuroimaging programme.
New connections
Topological analysis found markedly increased integration between cortical regions that ordinarily sit in separate networks, a pattern not seen under placebo.
Activity in hub regions
Cerebral blood flow and BOLD signal fell, with the strongest effects in the anterior cingulate and medial prefrontal cortex, posterior cingulate cortex and thalamus.
Default mode network
Coupling between the medial prefrontal cortex and posterior cingulate cortex, the core nodes of the default mode network, was reduced.
What the studies actually did
In 2012, a team at Imperial College London working with the Beckley Foundation used fMRI to image the brain during the psilocybin experience. The expectation in the field had been that a psychedelic would increase neural activity. The opposite was observed: activity and blood flow fell, most markedly in the brain's central connector hubs.1
Those hubs include the default mode network, a system associated with self referential thought, mind wandering and the ordinary running commentary of being a self. Psilocybin reduced the coupling between its two main nodes.1
Where the connectivity claim comes from
The 2014 paper applied a branch of mathematics called algebraic topology to the same kind of data and described the result as a homological scaffold: a map of how information routes through the brain. Under psilocybin, that map showed many more connections between regions that do not ordinarily communicate.2 This is the source of the widely reproduced image of two rings, placebo on one side and psilocybin on the other.
How the two findings fit together
The brain's hub regions normally act as gatekeepers, channelling information along well worn routes. When psilocybin quietens them, that constraint loosens, and regions that rarely exchange signals begin to do so.1 The thousands of new connections mapped in the 2014 analysis are what that opening looks like when it is measured.2
What this does not mean
Imaging research is easy to over-interpret, so here is what these studies do not establish.
- These were small imaging studies. Early neuroimaging work in this field used small samples of healthy volunteers, which limits how far the results generalise.1
- Brain changes are not outcomes. Observing that a network reorganises does not demonstrate that a person's life improves. The link between these images and any lasting benefit remains a research question.12
- A scanner is not a retreat. These sessions took place in a laboratory environment, which differs substantially from a retreat setting.1
- This is not a treatment claim. Psilocybin is not approved by the U.S. Food and Drug Administration for any medical indication yet.
References
Every figure and finding stated on this page traces to one of the sources below.
- Carhart-Harris, R.L., et al. Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. PNAS, 2012. Read the full text
- Petri, G., et al. Homological scaffolds of brain functional networks. Journal of the Royal Society Interface, 2014. View on PubMed