Possible roles for sleep states and neuromodulation in sleep-dependent plasticity

描述（申请人提供）：睡眠为什么存在的基本问题是有争议的[1]。睡眠在神经元可塑性中起作用的假设已经得到了关于皮质可塑性的典型模型的工作的支持，猫的眼优势可塑性（ODP）[2]。在猫的视觉皮层（VI）中，大多数神经元对任何一只眼睛的反应都一样好;然而，在生命早期剥夺一只眼睛的视觉输入（单眼剥夺，MD）会增加优先对非剥夺眼睛反应的细胞数量[3，4]。MD诱导的ODP被随后的睡眠增强，表明睡眠在可塑性的巩固中起作用[2]。此外，参与可塑性的几种蛋白质在MD后睡眠期间被激活[5]。然而，快速眼动（REM）和非快速眼动（NREM）睡眠状态在这一过程中的作用尚不清楚。这些状态都以独特的神经调节音调和离子通道激活为特征，并且可能在可塑性中发挥不同但互补的作用[6]。因此，本提案的目标是研究每种睡眠状态的要求（目标1）以及睡眠期间神经调质和离子通道活性（目标2）对睡眠依赖性ODP巩固的贡献。这些实验将深入了解神经回路发展的基本机制，以及新皮层记忆巩固，这被认为是长期记忆形成和维持的基础[7]。为了解决这些问题，猫将被植入电极来监测睡眠，并在清醒期间接受6小时的MD。在目标1中，这将是正常的，REM剥夺或NREM片段睡眠。NREM片段化是REM剥夺的非特异性效应的对照。在目标2中，MD之后将是睡眠，在此期间将神经调节剂和离子通道的特异性拮抗剂注入V1。对于这两个目标，两个实验方法将被用来量化操纵ODP合并的影响。首先，将使用内在皮层信号的光学成像和单个单元记录来评估操作对神经元活动的影响。第二，将使用Western印迹分析和免疫组织化学来量化操作对可塑性相关蛋白的活化的影响。 睡眠不足与许多身心健康问题有关，是影响当今社会的主要公共卫生问题[8]。这项研究将有助于阐明儿童时期睡眠不足对大脑发育的影响，以及对成年人认知功能以及记忆形成和维持的影响。

DESCRIPTION (provided by applicant): The fundamental question of why sleep exists is controversial [1]. The hypothesis that sleep plays a role in neuronal plasticity has been supported by work on a canonical model of cortical plasticity, ocular dominance plasticity (ODP) in the cat [2]. In the the cat visual cortex (VI), most neurons respond equally well to either eye; however, depriving one eye of visual input (monocular deprivation, MD) early in life increases the number of cells that respond preferentially to the non-deprived eye [3, 4]. ODP induction by MD is enhanced by subsequent sleep, indicating that sleep plays a role in the consolidation of plasticity [2]. Furthermore, several proteins involved in plasticity are activated during post-MD sleep [5]. However, the roles of rapid eye movement (REM) and non-REM (NREM) sleep states in this process are not understood. These states are both characterized by unique neuromodulatory tone and ion channel activation, and may play distinct but complementary roles in plasticity [6]. Therefore, the goal of this proposal is to investigate the requirement for each sleep state (Aim 1) and the contribution of neuromodulators and ion channel activity during sleep (Aim 2) to sleep-dependent ODP consolidation. These experiments will provide insight into fundamental mechanisms underlying the development of neural circuits, as well as neocortical memory consolidation, which is thought to underlie the formation and maintenance of long-term memory [7]. To address these questions, cats will be implanted with electrodes to monitor sleep and will undergo 6 hours of MD during waking. In Aim 1, this will be followed by normal, REM-deprived, or NREM-fragmented sleep. NREM fragmentation is a control for the nonspecific effects of REM deprivation. In Aim 2, MD will be followed by sleep during which specific antagonists of neuromodulators and ion channels will be infused into V1. For both aims, two experimental approaches will be used to quantify the impact of the manipulation on ODP consolidation. First, the effects of the manipulations on neuronal activity will be assessed using optical imaging of intrinsic cortical signals and single unit recording. Second, the effect of the manipulation on the activation of plasticity-related proteins will be quantified using Western blot analysis and immunohistochemistry. Getting inadequate amounts of sleep is linked to many physical and mental health issues and is a major public health problem that affects today's society [8]. This research will help elucidate the impact of sleep loss during childhood on brain development, as well as demonstrating the impact on cognitive function and the formation and maintenance of memories in adults.