Neuronal dynamics of the anterior cingulate cortex during working memory and serotonergic manipulation

The prefrontal cortex (PFC) plays a strong role in the execution of executive tasks such as working memory. It is thought to exert top-down control over sensory regions, and integrate information from both external stimuli, and internal computation, such as choice and expectation (1-3). The anterior cingulate cortex (ACC) is a region of the PFC known to receive strong projections from serotonergic neurons of the raphe nuclei (4). In the work presented here, the influence of the hallucinogenic compound, and serotonergic agonist, psilocybin, was investigated in the neural circuits of the ACC of awake, head-fixed mice. Extracellular, multi-unit recordings were performed to examine the effects of the systemic administration of psilocybin. Psilocybin was found to transition the network into a desynchronised state, reminiscent of REM sleep. This state was characterised by an increase in activation in the network, combined with a reduction in power of low frequency LFP oscillations in the delta, theta and alpha band, coupled with a moderate increase in power in the gamma frequency band. The encoding mechanisms in the ACC in working memory were examined by conducting similar recordings in mice performing a delayed... (continues)