Finding the self by losing the self: Neural correlates of ego-dissolution under psilocybin

Alexander V. Lebedev, Martin Lövdén, Gidon Rosenthal, Amanda Feilding, David J. Nutt, Robin L. Carhart-Harris

Research output: Contribution to journalArticlepeer-review

177 Scopus citations

Abstract

Ego-disturbances have been a topic in schizophrenia research since the earliest clinical descriptions of the disorder. Manifesting as a feeling that one's “self,” “ego,” or “I” is disintegrating or that the border between one's self and the external world is dissolving, “ego-disintegration” or “dissolution” is also an important feature of the psychedelic experience, such as is produced by psilocybin (a compound found in “magic mushrooms”). Fifteen healthy subjects took part in this placebo-controlled study. Twelve-minute functional MRI scans were acquired on two occasions: subjects received an intravenous infusion of saline on one occasion (placebo) and 2 mg psilocybin on the other. Twenty-two visual analogue scale ratings were completed soon after scanning and the first principal component of these, dominated by items referring to “ego-dissolution”, was used as a primary measure of interest in subsequent analyses. Employing methods of connectivity analysis and graph theory, an association was found between psilocybin-induced ego-dissolution and decreased functional connectivity between the medial temporal lobe and high-level cortical regions. Ego-dissolution was also associated with a “disintegration” of the salience network and reduced interhemispheric communication. Addressing baseline brain dynamics as a predictor of drug-response, individuals with lower diversity of executive network nodes were more likely to experience ego-dissolution under psilocybin. These results implicate MTL-cortical decoupling, decreased salience network integrity, and reduced inter-hemispheric communication in psilocybin-induced ego disturbance and suggest that the maintenance of “self”or “ego,” as a perceptual phenomenon, may rest on the normal functioning of these systems. Hum Brain Mapp 36:3137–3153, 2015.

Original languageEnglish
Pages (from-to)3137-3153
Number of pages17
JournalHuman Brain Mapping
Volume36
Issue number8
DOIs
StatePublished - 1 Aug 2015

Keywords

  • connectivity
  • consciousness
  • ego-disturbances
  • fMRI
  • graph theory
  • ichstörungen
  • medial temporal lobe
  • psychedelics
  • psychosis
  • sense of self

ASJC Scopus subject areas

  • Anatomy
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Clinical Neurology

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