Ca 2+ signaling in astrocytes is sleep-wake state specific and modulates sleep

Astrocytic Ca signaling has been intensively studied in health and disease but remains uncharacterized in sleep. Here, we employed a novel activity-based algorithm to assess astrocytic Ca signals in the barrel cortex of awake and naturally sleeping mice while monitoring neuronal Ca activity, brain rhythms and behavior. We discovered that Ca signaling in astrocytes exhibits distinct features across the sleep-wake cycle and is reduced in sleep compared to wakefulness. Moreover, an increase in astrocytic Ca signaling precedes transitions from slow-wave sleep to wakefulness, with a peak upon awakening exceeding the levels during whisking and locomotion. Genetic ablation of a key astrocytic Ca signaling pathway resulted in fragmentation of slow-wave sleep, yet increased the frequency of sleep spindles. Our findings suggest a role for astrocytic Ca signaling in modulating sleep.