The Geometry of Layer 2/3 Cortical Sound Processing in Slow Wave Sleep.

During wake, sound-evoked and spontaneous neural activity of the auditory cortex evolves in distinct subspaces, whereas anesthesia disrupts sound responses and merges these spaces. To evaluate if similar modifications of sound representation geometry explain sensory disconnection during sleep, large neural populations of the mouse auditory cortex are followed across slow-wave sleep and wakefulness. It is observed that sleep dampens sound responses but preserves the geometry of sound representations such that they remain separate from spontaneous activity. Moreover, response dampening is strongly coordinated across neurons and varied throughout sleep, spanning from fully preserved response patterns to population response failures on a fraction of sound presentations. These failures rarely occurred in wakefulness and are more common during high spindle-band activity. Therefore, in sleep, the auditory system preserves sound feature selectivity up to the cortex for detailed acoustic surveillance but concurrently implements an intermittent gating mechanism leading to local sensory disconnections.