Mechanisms of Mammalian Neuronal Integration

描述（由申请人提供）：了解哺乳动物中枢神经系统（CNS）中的单个神经元如何相互沟通，需要详细了解调节突触传递和突触后神经元（突触整合）突触信号处理的因素。在本项目中，我们将利用中央听觉通路中特定巨突触连接和突触后神经元提供的一些关键技术优势来解决这些问题。我们将研究正常和先天性耳聋动物中相同突触和神经元的特性，以深入了解活动在中枢通路中突触强度和突触后膜特性的发育和调节中的作用。突触传递和突触后整合有着千丝万缕的联系，我们的研究提供了一个极有价值的机会，可以尽可能全面地研究同一中枢神经元中的这两种现象。我们的目标是利用膜片钳记录来自萼轴突末端及其突触后神经元的突触和膜电流，同时使用免疫标记和电子显微镜来定位关键的突触和膜蛋白并确定突触结构，并使用计算方法来帮助理解特定离子通道在突触整合中的作用。目的是验证以下假设：在发育过程中听觉系统活动的改变(1)导致突触强度、结构、离子通道表达和神经元兴奋性的变化，以及(2)破坏听觉回路的正常张力组织。拟议的研究将使用详细的、多学科的方法来研究哺乳动物神经系统区域的突触结构、功能和整合，这对实现这一目标非常有利。两个经验丰富且富有成效的实验室的综合技能和资源将用于解决这些在哺乳动物中枢神经系统中迄今难以解决的基本问题。听觉神经元和突触的组织和几何形状允许电生理和免疫组织化学结果直接进行比较。所获得的结果将对理解突触传递和整合的机制具有普遍意义，并对理解慢性感觉剥夺条件下中枢听觉系统发生的变化具有临床意义。

DESCRIPTION (provided by applicant): Understanding how individual neurons in the mammalian central nervous system (CNS) communicate with each other requires detailed knowledge of the factors that regulate both synaptic transmission and the processing of synaptic signals by postsynaptic neurons (synaptic integration). In this project, we will address these issues by capitalizing on some key technical advantages offered by specific giant synaptic connections and postsynaptic neurons in central auditory pathways. We will study the properties of the same synapses and neurons in both normal and congenitally deaf animals, to gain insight into the role of activity in the development and regulation of synaptic strength and postsynaptic membrane properties in central pathways. Synaptic transmission and postsynaptic integration are inextricably linked - our study offers an extremely valuable opportunity to investigate both phenomena as comprehensively as possible in the same central neurons. Our aims employ patch-clamp recording of synaptic and membrane currents from calyceal axon terminals and their postsynaptic neurons, in parallel with immunolabeling and electron microscopy to localize key synaptic and membrane proteins and determine synaptic structure, and with computational methods to help understand the roles of specific ion channels in synaptic integration. The aims will test the hypotheses that altered auditory system activity during development (1) leads to changes in synaptic strength, structure, ion channel expression and neuronal excitability, and (2) disrupts the normal tonotopic organization of auditory circuits. The proposed research will use detailed, multidisciplinary approaches to study synaptic structure, function, and integration in a region of the mammalian nervous system that is highly advantageous for this purpose. The combined skills and resources of two experienced and productive laboratories will be brought to bear on these fundamental issues, which heretofore have been difficult to address in the mammalian CNS. The organization and geometry of auditory neurons and synapses allows electrophysiological and immunohistochemical results to be directly compared. The results to be obtained will be of general significance for understanding mechanisms of synaptic transmission and integration, and of clinical significance in understanding the changes that occur in the central auditory system under conditions of chronic sensory deprivation.