bioRxiv : the preprint server for biologyApr 27, 2026

Psilocybin changes brain's outer layer inhibition by targeting specific nerve cells

Psychedelic Science Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 27, 2026

Abstract

Essence

Psilocybin altered mouse frontal-cortex inhibition by oppositely shifting major interneuron types.

Evidence

This mouse preclinical study measured GABAergic cell-type activity and used pharmacological blockade plus conditional knockout experiments in medial frontal cortex.

Caveat

The evidence is from mice and cell-type mechanisms, so it does not show psychiatric treatment effects in humans.

Simplified

Psychedelics show therapeutic potential for treating psychiatric disorders. While studies have emphasized the roles of cortical pyramidal cells, GABAergic neurons also express serotonin receptors and are therefore likely targets of psychedelics. In this study, we determine the effect of psilocybin on the activity dynamics of major GABAergic cell types in the mouse medial frontal cortex. Psilocybin reduces the firing of somatostatin-expressing interneurons, but increases the activity of parvalbumin-expressing interneurons. This cell type-specific response is unlikely to involve vasoactive intestinal peptide-expressing interneurons. Instead, pharmacological blockade and conditional knockout experiments demonstrate that psilocybin acts on the 5-HT1A receptor at SST interneurons, which contributes to the drug's long-term behavioral effects. Collectively, the results reveal that the classic psychedelic psilocybin alters cortical inhibition in a cell type-specific manner.