Structure of modulation of neuronal firing rates across different brain state transitions.

Changes of brain state result in dramatic changes to spontaneous neuronal firing. In this work, we use multiple datasets of Neuropixels recordings from different brain regions to examine the modulation of firing rates across multiple examples of brain state transition, including those driven by both natural and pharmacological means. We show how this modulation impacts the distribution of firing rates across a transition and present a common structure of modulation across all examined changes of brain state. We consistently find that slow firing neurons are modulated more extensively and with greater inter-neuron variability than fast firing neurons. By incorporating the left-skewed distributions of log firing rates, we are able to encapsulate this modulation structure using bivariate log-gamma distributions. We further investigate the effects of the psychedelic brain state on the modulation of visual responses in the mouse primary visual cortex to differential stimuli based on feedforward and feedback processing. We find that psychedelics bidirectionally modulate visual responses and show a preferential facilitation of feedforward responses supporting the theory of sensory over-load in psychedelic perception.