Effective connectivity of emotion and cognition under psilocybin

Psilocybin reduces the brain's top-down control from resting state networks to the amygdala, which is involved in emotion appraisal and regulation. In a randomized, double-blind, placebo-controlled trial of 24 healthy adults given 0.215 mg/kg psilocybin, effective connectivity decreased from the default mode network and salience network to the amygdala, and within the DMN and SN, while connectivity within the central executive network increased. These changes were linked to altered emotion and meaning under the drug, suggesting that attenuation of the amygdala signal may serve as a biomarker for psilocybin's therapeutic effects in conditions like addiction and depression.

Study at a glance

Abstract

Abstract Classic psychedelics alter sense of self and patterns of self-related thought. These changes are hypothesised to underlie their therapeutic efficacy across internalising pathologies such as addiction and depression. Using resting-state functional MRI images from a randomised, double blinded, placebo-controlled clinical trial of 24 healthy adults under 0.215mg/kg psilocybin, we investigated how psilocybin modulates the effective connectivity between resting state networks and the amygdala that are involved in the appraisal and regulation of emotion and association with clinical symptoms. The networks included the default mode network (DMN), salience network (SN) and central executive network (CEN). Psilocybin decreased top-down effective connectivity from the resting state networks to the amygdala and decreased effective connectivity within the DMN and SN, while the within CEN effective connectivity increased. Effective connectivity changes were also associated with altered emotion and meaning under psilocybin. Our findings identify changes to cognitive-emotional connectivity associated with the subjective effects of psilocybin and the attenuation of the amygdala signal as a potential biomarker of psilocybin’s therapeutic efficacy.