Single-cell resolution functional networks during sleep are segregated into spatially intermixed modules

Abstract

The neural mechanisms responsible for the reduction of consciousness during sleep remain elusive. Previous studies investigating macro/mesoscale neural data have suggested that functional networks are segregated into spatially localized modules, and that these modules are more segregated during sleep than during wakefulness. However, large-scale single-cell resolution functional networks remain largely unexplored. Here, we simultaneously recorded the activities of up to 10,000 cortical neurons from multiple brain regions in mice during wakefulness and sleep using a fast, single-cell resolution, and wide-field-of-view two-photon calcium imaging technique. We examined how networks were integrated or segregated between brain states in terms of modularity and spatial distribution in the cortex. We found that modularity during non-rapid eye movement sleep was higher than that during wakefulness, indicating a more segregated network. However, these modules were not spatially localized but rather intermixed across regions in both states. Our results provide novel insights into differences in the cellular-scale organization of functional networks during altered states of consciousness.