Finding the self by losing the self: Neural correlates of ego-dissolution under psilocybin
Human Brain Mapping – May 22, 2015
Source: OpenAlex
Summary
The profound psychological experience of ego-dissolution, often induced by the hallucinogen psilocybin, is rooted in distinct brain alterations. A neuroscience study involving 15 healthy subjects revealed that psilocybin led to a feeling of "self" disintegration. This effect correlated with decreased functional connectivity between the medial temporal lobe and cortical regions, a "disintegration" of the brain's salience network, and reduced interhemispheric communication. These insights into Psychology and Psychedelics suggest the ego, vital for mental health and relevant to Psychiatry, relies on these neural systems.
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.