Spatiotemporal Brain Dynamics of Emotional Face Processing Modulations Induced by the Serotonin 1A/2A Receptor Agonist Psilocybin

Psilocybin, a serotonin receptor agonist, alters how the brain processes emotional faces. Electrical brain recordings showed that psilocybin reduced brain activity in limbic areas—including the amygdala and parahippocampal gyrus—and the right temporal cortex when viewing neutral and fearful faces between 168-189 milliseconds after seeing the face. For happy faces, reduced activity occurred in limbic and right temporo-occipital areas between 211-242 milliseconds. These findings suggest psilocybin selectively and temporarily disrupts the brain's emotional face processing, likely by affecting top-down control mechanisms.

Study at a glance

Abstract

Emotional face processing is critically modulated by the serotonergic system. For instance, emotional face processing is impaired by acute psilocybin administration, a serotonin (5-HT) 1A and 2A receptor agonist. However, the spatiotemporal brain mechanisms underlying these modulations are poorly understood. Here, we investigated the spatiotemporal brain dynamics underlying psilocybin-induced modulations during emotional face processing. Electrical neuroimaging analyses were applied to visual evoked potentials in response to emotional faces, following psilocybin and placebo administration. Our results indicate a first time period of strength (i.e., Global Field Power) modulation over the 168-189 ms poststimulus interval, induced by psilocybin. A second time period of strength modulation was identified over the 211-242 ms poststimulus interval. Source estimations over these 2 time periods further revealed decreased activity in response to both neutral and fearful faces within limbic areas, including amygdala and parahippocampal gyrus, and the right temporal cortex over the 168-189 ms interval, and reduced activity in response to happy faces within limbic and right temporo-occipital brain areas over the 211-242 ms interval. Our results indicate a selective and temporally dissociable effect of psilocybin on the neuronal correlates of emotional face processing, consistent with a modulation of the top-down control.