Psilocybin reshapes cortical inhibition through selective interneuron recruitment

Area of Science:

• Neuroscience
• Psychopharmacology
• Cell Biology

Background:

• Psychedelics like psilocybin show promise for psychiatric disorders.
• GABAergic neurons, crucial for brain inhibition, are potential psychedelic targets due to serotonin receptor expression.

Purpose of the Study:

• To investigate the effects of psilocybin on the activity dynamics of distinct GABAergic interneuron populations in the mouse medial frontal cortex.
• To elucidate the specific cell types and molecular mechanisms through which psilocybin modulates cortical activity.

Main Methods:

• Electrophysiological recordings in mouse medial frontal cortex.
• Pharmacological blockade of specific serotonin receptors.
• Conditional knockout of target receptors in specific interneuron populations.

Main Results:

• Psilocybin differentially affects GABAergic interneurons: it reduces firing in somatostatin-expressing (SST) interneurons but increases activity in parvalbumin-expressing (PV) interneurons.
• The observed cell-type-specific effects are not mediated by vasoactive intestinal peptide (VIP) interneurons.
• Psilocybin's action on SST interneurons involves the 5-HT1A receptor, contributing to its long-term behavioral outcomes.

Conclusions:

• Psilocybin induces cell type-specific alterations in cortical inhibition, impacting distinct GABAergic neuron populations.
• The 5-HT1A receptor on SST interneurons is a key mediator of psilocybin's effects on cortical circuits and behavior.
• These findings highlight the nuanced mechanisms underlying psychedelic action in the brain and their therapeutic potential.