Psilocybin, the psychoactive compound found in “magic” mushrooms, has shown promising antidepressant effects in both humans and rodent models. These therapeutic effects are thought to involve modulation of the medial prefrontal cortex (mPFC), a brain region implicated in depression pathology. This study presents preliminary electrophysiological evidence suggesting that psilocybin alters the excitation-to-inhibition balance in the mPFC, potentially contributing to its antidepressant properties. In vivo recordings from rodent mPFC neurons revealed divergent responses to psilocybin administration, with increased activity in GABAergic-like neurons and decreased activity in glutamatergic-like neurons. These findings support the hypothesis that psilocybin enhances inhibitory signaling within the mPFC, thereby reducing overall excitatory activity. Such a shift in network dynamics may promote greater brain flexibility and counteract rigid depressive states. Future research aims to further characterize the specific cell types involved, investigate other psychedelics with similar effects, and assess the long-term behavioral implications of psilocybin-induced neurophysiological changes.
Psilocybin, the primary psychoactive compound in “magic” mushrooms, exerts antidepressant effects in humans and rodents.
Depression has been correlated with increased activity of the medial prefrontal cortex (mPFC).
It is hypothesized psilocybin preferentially activates inhibitory cells within the mPFC leading to decreased global mPFC activity, which is theorized to contribute to antidepressant effects.
Psilocybin “resets” network dynamics in the mPFC, increasing brain flexibility and reducing rigid depressive states (Carhart-Harris et al., 2017).
Both depression and psychedelics act on the medial prefrontal cortex (mPFC). This region is a key target in both pathology and treatment.
Previous studies have shown augmented activity in the mPFC to correlate with severity of depression.
Signaling imbalance between excitatory Glutamatergic and inhibitory GABAergic mPFC cells may underlie depression; restoring this balance with psychedelics (i.e., psilocybin) may lead to antidepressant effects.
Diagram illustrates the synaptic connection between a glutamate neuron and GABA interneurons in the medial prefrontal cortex, highlighting inhibitory regulation of excitatory signaling.
Disclosure: Jones & McMurray are members of the scientific advisory board of PsyBio Therapeutics. PsyBio Therapeutics provided support for this work.