Research Projects

Investigating Changes in Cerebral Blood Flow and Remote Memory Access Brought About by Psilocybin

Prof. David Nutt, University of Bristol
Dr Robin Carhart-Harris, Imperial College, London
Amanda Feilding, Beckley Foundation, Oxford

For many years Amanda Feilding has been working at opening up psychedelic research in the UK. Finally she has been successful in initiating and collaborating on a project that is currently being managed by Dr Robin Carhart-Harris under the supervision of Professor David Nutt, Head of Neuropsychopharmacology at Imperial College London, and Chair of the Independent Scientific Committee on Drugs. This landmark project involves investigating the effects of psilocybin on brain activity and blood flow, using the advanced functional brain imaging technique fMRI.

We have already begun measuring changes in brain blood flow after psilocybin using the fMRI technique Arterial Spin Labelling (ASL), but have not yet analysed the results. We have already completed an earlier pilot study assessing the participants’ toleration of psilocybin in a mock-fMRI environment. The current ASL fMRI work will provide information on how psilocybin elicits its subjective effects in the brain and may also inform our understanding of the neurobiology of psilocybin-induced mystical-type experiences, and of interpersonal and existential experiences relevant to psychotherapeutic applications of psilocybin.

This study will examine the hypothesis that psilocybin enables vivid recall of remote and inaccessible memories, thereby enabling people more readily to re-activate repressed emotional memories. A facilitatory effect of psilocybin on memory recall would be of great help in treating many psychological disorders. The study will also measure the brain activity after ingesting psilocybin, using the Blood Oxygen Level Dependent (BOLD) signal of fMRI. BOLD fMRI will allow us to look at changes in regional brain activity and in interregional connectivity after psilocybin, which should give us a much clearer impression of how psilocybin elicits its subjective effects. This work is truly pioneering and we are pleased to have the collaborative support of a world leader in fMRI, Professor Karl Friston, Scientific Director of the Wellcome Trust Centre for Neuroimaging in London. Prof. Friston is the fourth most-cited neuroscientist in the world. This work may well have implications for the science of psychotherapy and our understanding of the mind in general.

A facilitatory effect of psilocybin on memory recall would be of great help in treating depression and other mood disorders. Indeed, the research will focus on the potential of using psilocybin as a means of enhancing efforts to overcome treatment resistant depression. We will examine carefully the effects of psilocybin vs. placebo on the subgenual cingulate cortex and its connectivity to other regions of the brain as this cortical area has been particularly implicated in intractable depression and its possible treatment.

If the hypotheses regarding psilocybin's effects on memory retrieval are supported, this pilot study will then be used as the basis to develop a proposal for a much more extensive clinical trial involving patients with treatment resistant depression. This project therefore has the potential to provide a new way of treating a most distressing and growing problem in our society, and also further develop our understanding of the neurobiological effects of psychedelics and how they might be used to the benefit of mankind.