Neuronal circuit controlling sleep-promoting ventrolateral preoptic neurons

项目摘要/摘要 睡眠是一个活跃的过程，需要促进睡眠的细胞群体的分隔节点的参与。 过去二十年的研究表明，在腹外侧视前区有甘丙素表达的神经元 (VLPOGal)神经元是正常睡眠和皮质慢波活动所必需的。然而，仍然存在 我们对VLPOGal神经元的细胞和突触基础的理解中的几个基本差距 都是受监管的。行为睡眠-唤醒控制的一个非常有影响力的电路模型是 睡眠-状态转换，它提出睡眠-觉醒转换受相互抑制的调节 促眠VLPOGal神经元与单胺能和胆碱能促醒结节之间的关系 前脑和脑干。发现VLPO和VLPO之间存在相互的解剖学联系 单胺和胆碱能神经元，这些细胞群分别表现出睡眠和觉醒活动 射击轮廓为该模型提供了总体支持。然而，VLPO从以下位置接收输入 许多其他来源包括直接参与睡眠和睡眠的非胆碱能和非单胺能神经元 唤醒法规。我们最近发现，激活下丘脑外侧区的GABA能神经元 通过直接抑制VLPOGal神经元而有效地促进唤醒。在这里，我们试图通过以下方式扩展这一发现 识别其他控制觉醒水平的潜在突触驱动，包括远程和局部 突触驱动。为此，虽然一段时间以来人们已经意识到VLPOGal神经元处于局部 关于突触的控制，这个VLPO内回路的细节在很大程度上仍不清楚。我们发现， VLPOGal神经元直接受到一组局部GABA能神经元的抑制。我们建议这个当地的 GABA能回路作为共同的入路节点，通过其传入觉醒和睡眠促进通路 控制VLPOGal神经元，具体假设如下：1)直接和前馈抑制 产生唤醒和2)解除对VLPOGal神经元的抑制以产生睡眠。因此，目前的提案寻求 首先在体外，然后在体内识别直接或间接调节VLPOGal的远程传入输入 神经元通过局部GABA能网络驱动行为和大脑皮层觉醒。要做到这一点，我们首先 应用于VLPO特异性AIMS 1体外环路定位和GABA能传递的局灶性缺失 以确定控制VLPOGal神经元的局部GABA能回路的必要性。在……里面 特定目标2我们将通过体外记录确定VLPO中的突触后神经元 促进觉醒和睡眠的输入。最后，在特定的目标3中，我们将使用活体光遗传学来测试 在体外首次确定的VLPO的传入输入是产生睡眠和觉醒行为所必需的 改变和纤维光度法检测这些传入对VLPO的状态依赖性活动。给定 这项提议试图填补巨大的知识缺口，我们期待这一协作工作的成果能够提供 对支持睡眠和清醒调节的大脑回路的重要和新颖的见解。

Project Summary/Abstract Sleep is an active process requiring the participation of delimited nodes of sleep-promoting cell populations. Work over the last twenty years has demonstrated that galanin expressing neurons in the ventrolateral preoptic (VLPOGal) neurons are necessary for normal sleep and cortical slow wave activity. There remain however several fundamental gaps in our understanding of the cellular and synaptic basis by which VLPOGal neurons are regulated. One highly influential circuit model for behavioral sleep-wake control is the `flip-flop' model of sleep-state switching, which proposes that sleep-wake transitions are regulated by a reciprocal inhibition between sleep-promoting VLPOGal neurons and monoaminergic and cholinergic wake-promoting nodes of the forebrain and brainstem. The findings that reciprocal anatomical connections exist between the VLPO and monoamine and cholinergic neurons and that these cell groups exhibit, respectively, sleep- and wake-active firing profiles have provided general support for the model. However, the VLPO receives afferent inputs from many other sources including non-cholinergic and non-monoaminergic neurons directly involved in sleep and wake regulation. We have recently found that activation of GABAergic neurons of the lateral hypothalamus potently promotes arousal by directly inhibiting VLPOGal neurons. Here we seek to extend this finding by identifying other potential synaptic drives that control arousal levels, including both long-range and local synaptic drives. To this end, while it has been appreciated for some time that VLPOGal neurons are under local synaptic control, the details of this intra-VLPO circuit remains largely uncharacterized. We have found that VLPOGal neurons are directly inhibited by a group of local GABAergic neurons. We propose that this local GABAergic circuit serves as common entry node through which afferent wake- and sleep-promoting pathways control VLPOGal neurons, with the specific hypotheses that this occurs by 1) direct and feedforward inhibition to produce arousal and 2) disinhibition of VLPOGal neurons to produce sleep. The current proposal thus seeks to identify, first in vitro and then in vivo, the long-range afferent inputs that directly or indirectly regulate VLPOGal neurons to drive behavioral and cortical arousal via the local GABAergic network. To do so, we will first employ in Specific Aims 1 in vitro circuit mapping and focal deletion of GABAergic transmission in VLPO neurons to determine the necessity of the local GABAergic circuit for the control of VLPOGal neurons. In Specific Aim 2 we will identify with in vitro recordings the postsynaptic neurons in VLPO that are targeted by wake- and sleep-promoting inputs. Finally, in Specific Aim 3 we will use in vivo optogenetics to test whether the afferent inputs to the VLPO first identified in vitro slices are necessary to produce sleep and wake behavioral changes and fiber photometry to examine the state-dependent activity of these afferents to VLPO. Given the large knowledge gap this proposal seeks to fill, we expect results from this collaborative work to provide important and novel insights into the brain circuitry supporting sleep and wake regulation.