SYNAPTIC ORGANIZATION OF AUDITORY SYSTEM

本课题旨在研究听觉的结构基础 下丘（IC）的信息处理。 拟议 实验集中在突触组织的各个组成部分 它们是：1）由来自大脑皮层的传入轴突形成的突触接触， （2）IC的内在回路; （3）结构与神经支配相结合的下丘神经元 这些输入产生对听觉信号的反应。 拟议 实验中，我们将使用光（LM）和电子显微镜（EM）技术 收件人： 1.识别脑干传入通路的突触特征， 它们在IC中的双耳交互。 这包括以下实验： 建立耳蜗神经核传入神经的双侧会聚 IC神经元与轴突运输和变性技术在LM和 电磁水平。 B）直接显示耳蜗的突触后终止 用Golgi-EM在IC中特定细胞类型上的核传入， 退化方法 c）区分形态学和突触接触 由来自上级橄榄复合体和背核的传入神经发出 外侧丘系 2.通过EM分析识别IC中的内在轴突类型， 注射HRP和高尔基体浸渍的轴突及其末梢。 3.确定IC中哪些轴突类型可能使用GABA作为递质， 用EM鉴定优先积累3 H-GABA的那些 放射自显影法 4.研究树突的形态和突触的模式 神经支配的生理特征，HRP注射IC神经元与 LM和EM技术。 5.用顺行轴突识别IC的新皮质传入 运输和EM放射自显影方法。

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.