Mechanisms of Mammalian Neuronal Integration

描述(申请人提供)：要了解哺乳动物中枢神经系统(CNS)中单个神经元如何相互通信，需要详细了解调节突触传递和突触后神经元处理突触信号的因素(突触整合)。在这个项目中，我们将通过利用中枢听觉通路中特定的巨型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突触强度和突触后膜特性的发展和调节中的作用。突触传递和突触后整合是密不可分的--我们的研究为在同一个中枢神经元中尽可能全面地研究这两种现象提供了一个极其宝贵的机会。我们的目标是利用膜片钳记录来自肾盏轴突终末及其突触后神经元的突触和膜电流，同时结合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，并利用计算方法帮助理解特定离子通道在突触整合中的作用。AIMS将检验以下假设：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)扰乱听觉回路的正常音调组织。这项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中对此非常有利的区域的突触结构、功能和整合。两个经验丰富和富有成效的实验室的综合技能和资源将用于这些基本问题，到目前为止，这些问题在哺乳动物中枢神经系统中很难解决。听觉神经元和突触的组织和几何形状使电生理和免疫组织化学结果可以直接进行比较。这些结果对了解突触传递和整合的机制具有普遍意义，对于了解慢性感觉剥夺条件下中枢听觉系统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.