SYNAPTIC ORGANIZATION OF AUDITORY SYSTEM

本项目旨在研究听觉的结构基础。 下丘(IC)的信息处理。建议数 实验重点放在突触组织的各个组成部分上 它们是：1)由传入轴突形成的突触接触 IC中的脑干和新皮质：2)IC中的内在电路； 3)中枢神经元，其结构与神经支配相统一 这些输入产生对听觉信号的反应。在建议的 我们将使用光(LM)和电子显微镜(EM)技术进行实验 致： 1.识别脑干传入通路的突触特征 他们在IC中进行双耳交互。这包括以下实验：a) 单侧耳蜗核传入纤维双侧汇聚的建立 应用轴突运输和变性技术的丘脑室旁核和下丘脑的IC神经元 EM级别。B)直接显示耳蜗突触后终止 高尔基-EM核内特定细胞类型的核传入 退化方法。C)区分形态和突触接触 由上橄榄复合体和丘脑背侧核的传入纤维组成 外侧丘疹。 2.通过对大脑中隔核内固有轴突的EM分析，确定其类型。 HRP注射和高尔基体染色的轴突及其终末。 3.通过以下方式确定IC中的哪些轴突类型可能使用GABA作为递质 EM法鉴定优先积累~3H-GABA的基因 放射自显影方法。 4.观察突触的树突形态和形态 生理特征的HRP注射的IC神经元的神经支配 光镜和电子显微镜技术。 5.识别具有顺行轴突的IC的新皮质传入 运输法和EM放射自显影法。

This project is designed to investigate the structural basis for auditory information processing in the inferior colliculus (IC). The proposed experiments focus on the individual components of the synaptic organization which are: 1) the synaptic contacts formed by afferent axons from the brainstem and neocortex in the IC; 2) the intrinsic circuitry in the IC; and 3) the neurons of the IC whose structure and innervation integrate these inputs to produce responses to auditory signals. In the proposed experiments we will use light (LM) and electron microscopic (EM) techniques to: 1. Identify the synaptic features of brainstem afferent pathways and relate them to binaural interactions in the IC. This includes experiments to: a) Establish the bilateral convergence of cochlear nucleus afferents on single IC neurons with axonal transport and degeneration techniques at the LM and EM level. b) Demonstrate directly the postsynaptic termination of cochlear nucleus afferents on specific cell types in the IC with Golgi-EM and degeneration methods. c) Distinguish the morphology and synaptic contacts made by afferents from the superior olivary complex and dorsal nucleus of the lateral lemniscus. 2. Identify the types of intrinsic axons in the IC through EM analysis of HRP-injected and Golgi-impregnated axons and their endings. 3. Determine which axon types in the IC might use GABA as a transmitter by identifying those which preferentially accumulate 3H-GABA with EM autoradiographic methods. 4. Investigate the dendritic morphology and patterns of synaptic innervation of physiologically characterized, HRP-injected IC neurons with LM and EM techniques. 5. Identify the neocortical afferents to the IC with anterograde axonal transport and EM autoradiography methods.