Sakai K
Integrative Physiology of the Brain Arousal System, Lyon Neuroscience Research Center, INSERM U1028-CNRS UMR5292, School of Medicine, Claude Bernard University, F-69373, Lyon, France.
Neuroscience. 2015 Dec 3;310:455-71. doi: 10.1016/j.neuroscience.2015.09.063. Epub 2015 Sep 28.
A total of 211 neurons that discharged at the highest rate during sleep (sleep-active neurons) were recorded in non-anesthetized, head-restrained mice during the complete wake-sleep cycle in, and around, the laterodorsal (LDT) and sublaterodorsal (SubLDT) tegmental nuclei, which contain both cholinergic and non-cholinergic neurons. For the first time in mice, I reveal the presence, mainly in the SubLDT, of sleep-specific neurons displaying sustained tonic discharge either (i) just prior to, and during, paradoxical sleep (PS) (PS-on neurons) or (ii) during both slow-wave sleep (SWS) and PS (SWS/PS-on neurons). Both the PS-on and SWS/PS-on neurons showed either a low (< 10 Hz) or high (⩾ 10 Hz) rate of spontaneous firing and exhibited a biphasic narrow or medium-to-broad action potential, a characteristic of non-cholinergic neurons. At the transition from SWS to waking (W), the PS-on and SWS/PS-on neurons simultaneously ceased firing shortly before the onset of W, whereas, at the transition from W to SWS, only the SWS/PS-on neurons fired shortly after the onset of sleep. At the transition from SWS to PS, only the PS-on neurons exhibited a significant increase in discharge rate before PS onset, while, at the transition from PS to W, the SWS/PS-on neurons, then the PS-on neurons, displayed a significant decrease in the discharge rate before the end of PS. The SWS/PS-on neurons were more sensitive to the change in the electroencephalogram (EEG) than the PS-on neurons, as, during a PS episode, the slightest interruption of rhythmic theta activity resulted in cessation of discharge of the SWS/PS-on neurons. These findings support the view that, in the mouse SubLDT, PS-on neurons play an important role in the induction, maintenance, and cessation of PS, while SWS/PS-on neurons play a role in the maintenance of the PS state in particular and the sleep state in general.
在完全清醒 - 睡眠周期中，于未麻醉、头部固定的小鼠的外侧背盖（LDT）和外侧背盖下核（SubLDT）及其周围区域，共记录到211个在睡眠期间放电频率最高的神经元（睡眠活跃神经元），这些核团包含胆碱能和非胆碱能神经元。我首次在小鼠中揭示，主要在SubLDT中存在睡眠特异性神经元，它们在（i）异相睡眠（PS）之前及期间（PS开启神经元）或（ii）慢波睡眠（SWS）和PS期间（SWS/PS开启神经元）表现出持续的强直放电。PS开启神经元和SWS/PS开启神经元均表现出自发放电频率低（<10 Hz）或高（⩾10 Hz），并呈现双相窄或中到宽的动作电位，这是非胆碱能神经元的特征。从SWS过渡到清醒（W）时，PS开启神经元和SWS/PS开启神经元在W开始前不久同时停止放电，而从W过渡到SWS时，只有SWS/PS开启神经元在睡眠开始后不久放电。从SWS过渡到PS时，只有PS开启神经元在PS开始前放电率显著增加，而从PS过渡到W时，SWS/PS开启神经元，然后是PS开启神经元，在PS结束前放电率显著降低。SWS/PS开启神经元比PS开启神经元对脑电图（EEG）的变化更敏感，因为在PS发作期间，节律性θ活动的最轻微中断都会导致SWS/PS开启神经元停止放电。这些发现支持了这样一种观点，即在小鼠SubLDT中，PS开启神经元在PS的诱导、维持和停止中起重要作用，而SWS/PS开启神经元尤其在PS状态的维持以及总体睡眠状态的维持中起作用。
