Mammalian sleep expression and regulation have historically been thought to reflect the activity of neurons. Changes in other brain cells (glia) across the sleep-wake cycle and their role in sleep regulation are comparatively unexplored. We show that sleep and wakefulness are accompanied by state-dependent changes in astroglial activity. Using a miniature microscope in freely behaving mice and a two-photon microscope in head-fixed, unanesthetized mice, we show that astroglial calcium signals are highest in wake and lowest in sleep and are most pronounced in astroglial processes. We also find that astroglial calcium signals during non-rapid eye movement sleep change in proportion to sleep need. In contrast to neurons, astrocytes become less synchronized during non-rapid eye movement sleep after sleep deprivation at the network and single-cell level. Finally, we show that conditionally reducing intracellular calcium in astrocytes impairs the homeostatic response to sleep deprivation. Thus, astroglial calcium activity changes dynamically across vigilance states, is proportional to sleep need, and is a component of the sleep homeostat.

哺乳动物的睡眠表达和调节历来被认为反映了神经元的活动。其他脑细胞（神经胶质细胞）在睡眠-觉醒周期中的变化及其在睡眠调节中的作用相对尚未被探索。我们证明睡眠和清醒伴随着星形胶质细胞活动的状态依赖性变化。在自由行为的小鼠中使用微型显微镜，在头部固定、未麻醉的小鼠中使用双光子显微镜，我们发现星形胶质细胞钙信号在清醒时最高，在睡眠时最低，并且在星形胶质细胞过程中最明显。我们还发现，非快速动眼睡眠期间星形胶质细胞钙信号的变化与睡眠需求成比例。与神经元相反，星形胶质细胞在睡眠剥夺后的非快速眼动睡眠期间在网络和单细胞水平上变得不太同步。最后，我们发现有条件地减少星形胶质细胞中的细胞内钙会损害对睡眠剥夺的稳态反应。因此，星形胶质细胞钙活性在警觉状态下动态变化，与睡眠需求成正比，并且是睡眠稳态的组成部分。