Rapid eye movement (REM) and non-REM (NREM) sleep are controlled by specific neuronal circuits. Here we show that galanin-expressing GABAergic neurons in the dorsomedial hypothalamus (DMH) comprise separate subpopulations with opposing effects on REM versus NREM sleep. Microendoscopic calcium imaging revealed diverse sleep-wake activity of DMH GABAergic neurons, but the galanin-expressing subset falls into two distinct groups, either selectively activated (REM-on) or suppressed (REM-off) during REM sleep. Retrogradely labeled, preoptic area (POA)-projecting galaninergic neurons are REM-off, whereas the raphe pallidus (RPA)-projecting neurons are primarily REM-on. Bidirectional optogenetic manipulations showed that the POA-projecting neurons promote NREM sleep and suppress REM sleep, while the RPA-projecting neurons have the opposite effects. Thus, REM/NREM switch is regulated antagonistically by DMH galaninergic neurons with intermingled cell bodies but distinct axon projections.

中文翻译：

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一种用于快速眼动和非快速眼动睡眠的下丘脑开关。

快速眼动（REM）和非快速眼动（NREM）睡眠是由特定的神经元回路控制的。在这里，我们显示在背侧下丘脑（DMH）中表达甘丙肽的GABA能神经元包含单独的亚群，对REM和NREM睡眠的作用相反。显微内窥镜钙成像显示DMH GABA能神经元具有多种睡眠觉醒活性，但表达甘丙肽的亚组分为两个不同的组，在REM睡眠过程中选择性激活（REM-on）或抑制（REM-off）。逆行标记的，投射到视前区（POA）的加拉尼能神经元是REM-off，而投射出麻痹（RPA）的神经元主要是REM-on。双向光遗传学操作表明，投射POA的神经元可促进NREM睡眠并抑制REM睡眠，而投射RPA的神经元则具有相反的作用。因此，