REM mechanisms in neocortical development

描述（由申请人提供）：眼优势可塑性是由双眼视觉变化触发的体内突触可塑性的典型形式。它为了解大脑皮层回路在生命早期是如何发育和重塑的提供了重要的见解。我们已经表明，眼优势可塑性是巩固通过细胞机制类似于那些介导的长时程突触增强（LTP）。我们的目标是更完整地识别这些机制以及它们发生的大脑状态。为了实现这一目标，我们将使用我们建立的方法引发眼优势可塑性结合行为状态监测，失活的皮质内酶，光学成像的内在皮质信号，急性单神经元电生理学在体内，慢性四极记录的单神经元在自由行为的动物，和皮质蛋白质的蛋白质印迹测量。这些技术结合在一个简单的实验设计中，使我们能够确定不同的大脑状态和细胞内信号通路如何促进皮层电路的持久修改。更具体地说，我们将检验以下假设a）快速眼动（REM）睡眠对于巩固眼优势可塑性是必要的B）这是由REM睡眠中激活的蛋白激酶（Ca 2 +/钙调蛋白依赖性蛋白激酶[CaMK II]和细胞外调节激酶[ERK]）介导的。我们提出以下具体目标：1。确定REM睡眠在巩固眼优势可塑性中的作用。在这个目标中，我们将研究不同的快速眼动睡眠时间对两种不同类型的皮层可塑性的影响 这需要加强视觉回路。这将通过定量测量和操纵自由行为动物的警觉状态和初级视觉皮层的双眼视觉输入来实现。其次是三个独立的和客观的措施，在体内皮层可塑性（急性和慢性单神经元电生理学和光学成像的内在皮层信号）。2.确定CaMKII和ERK在眼优势可塑性巩固中的作用。在这个目标中，我们将研究CaMKII和ERK信号在睡眠期间发生的皮层回路加强中的作用。这将通过a）测量在不同量的视觉体验和快速眼动睡眠后处死的动物的初级视觉皮层中的总的和磷酸化的CaMK II和ERK蛋白B）确定皮层内泛CaMK的作用，选择性CaMKII和ERK抑制对眼优势可塑性的巩固c）然后使用模拟和闭塞实验来确定REM睡眠的作用是否由CaMK、CaMK II或ERK激酶活性介导。我们的研究结果将为经验和内源性大脑活动如何指导皮层回路的发育和可塑性提供新的见解。他们还将提供有关正常和异常睡眠如何影响哺乳动物大脑发育的新信息。 公共卫生相关性：这项提案中的研究将为快速眼动（REM）睡眠如何促进大脑皮层的关键发育过程提供重要的新见解。这将提高我们对正常和病理性大脑发育以及早期生活中睡眠功能的理解。

DESCRIPTION (provided by applicant): Ocular dominance plasticity is a canonical form of synaptic plasticity in vivo triggered by changes in binocular vision. It has provided crucial insights into how cortical circuits develop and remodel in early life. We have shown that ocular dominance plasticity is consolidated via cellular mechanisms similar to those mediating long-term synaptic potentiation (LTP). Our goal is to more completely identify these mechanisms and the brain states in which they occur. To achieve this goal we will use our established methods of eliciting ocular dominance plasticity combined with behavioral state monitoring, inactivation of intracortical enzymes, optical imaging of intrinsic cortical signals, acute single-neuron electrophysiology in vivo, chronic tetrode recording of single-neurons in freely-behaving animals, and Western blot measurements of cortical proteins. These techniques are combined in a simple experimental design that allows us to determine how different brain states and intracellular signaling pathways promote long-lasting modifications of cortical circuitry. More specifically, we will test the following hypotheses a) rapid-eye-movement (REM) sleep is necessary for the consolidation of ocular dominance plasticity b) this is mediated by protein kinases (Ca2+/calmodulin- dependent protein kinase [CaMKII] and extracellular regulated kinase [ERK]) activated in REM sleep. We propose the following Specific Aims: 1. Determine the role of REM sleep in the consolidation of ocular dominance plasticity. In this Aim, we will examine the effects of different amounts of REM sleep on two different types of cortical plasticity that require strengthening of visual circuits. This will be accomplished by quantitatively measuring and manipulating vigilance states and binocular visual input to primary visual cortex in the freely-behaving animal. This is followed by three independent and objective measures of cortical plasticity in vivo (acute and chronic single-neuron electrophysiology and optical imaging of intrinsic cortical signals). 2. Determine the role of CaMKII and ERK in the consolidation of ocular dominance plasticity. In this Aim, we will examine the role of CaMKII and ERK signaling in the strengthening of cortical circuits that occurs during sleep. This will be achieved by a) measuring total and phosphorylated CaMKII and ERK proteins in the primary visual cortices of animals that are sacrificed after different amounts of visual experience and rapid- eye-movement sleep b) determining the effects of intracortical pan-CaMK, selective CaMKII and ERK inhibition on the consolidation of ocular dominance plasticity c) mimicry and occlusion experiments are then used to determine if the effects of REM sleep are mediated by CaMK, CaMKII or ERK kinase activity. The results of our investigations will provide new insights into how experience and endogenous brain activity guide cortical circuit development and plasticity. They will also provide new information about how normal and abnormal sleep impacts mammalian brain development. PUBLIC HEALTH RELEVANCE: The research in this proposal will provide important new insights into how rapid-eye-movement (REM) sleep promotes critical developmental processes in the cerebral cortex. This will improve our understanding of normal and pathological brain development and the function of sleep in early life.