Psilocybin prevents habituation to familiar stimuli and preserves sensitivity to sound following repeated stimulation in mouse primary auditory cortex.
Psilocybin, a psychoactive substance derived from fungi, has been utilized historically by diverse cultures for both medicinal and non-medicinal purposes, owing to its ability to elicit profound sensory and cognitive alterations and sustain long-term changes in mood and cognition. Promising results from recent clinical studies have generated a wave of interest in employing psilocybin to treat neuropsychiatric and neuro-degenerative conditions. How psychedelics cause acute perceptual effects, and how these relate to long-lasting alterations is still debated. Whereas it is thought that perceptual disturbances may be caused by disrupted flow of information between sensory and higher order areas, in vivo studies have focused mostly on the latter. In particular, there has been little study of how psilocybin affects sensory representations in primary auditory cortex (A1). We used two-photon microscopy and wide field calcium imaging to examine how psilocybin affects A1 neuron response properties in the mouse. Administration of 1 mg/kg psilocybin prevented habituation of sound-evoked responses to repeated stimuli, maintaining overall responsiveness, bandwidth, and sound-level response thresholds after repeated stimulation. This was in contrast to marked habituation of responses and narrowing of tuning in controls. We observed no effect on overall distribution of best frequencies at the cortical level, suggesting psilocybin in A1 disrupts normal sensory gating, rather than tonotopic organization. This supports models of psychedelic action in which perceptual disturbances are driven by disrupted hierarchical sensory gating. With further research, influences of psychedelics on sensory representations could be harnessed to target maladaptive sensory processing in conditions such as tinnitus. Significance StatementDespite its role in altering auditory sensory perception, the impact of psilocybin on modulating neuronal activity in the auditory cortex remains understudied. This study is the first to identify an inhibition of normal auditory habituation to repeated stimuli with single-neuron resolution. We identify a role for psilocybin in the targeted, context-dependent modulation of auditory sensory neural tuning properties, which may help to explain how disruption of hierarchical control of sensory representations leads to perceptual disturbances. With further work, this influence on sensory representations could be used to target conditions where maladaptive sensory processing leads to deleterious health outcomes.