DESCENDING PROJECTIONS TO THE COCHLEAR NUCLEI

耳蜗核的下降投射

• 批准号: 3461848
• 负责人: GEORGE A SPIROU
• 金额: $ 12.31万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3461848
• 关键词: acetylcholine; auditory feedback; auditory nuclei; auditory pathways; brain mapping; brain stem; cats; cell type; cochlear microphonic potentials; cochlear nerve; decerebration; electrophysiology; excitatory aminoacid; guinea pigs; hearing; histology; iontophoresis therapy; lectin; middle ear; morphology; neural information processing; neural inhibition; neuroanatomy; neurons; neurophysiology; noise; olivary body; olivocochlear bundle

The goal of this project is to understand the roles of local feedback systems to the cochlear nuclei in shaping the neural representation of sound for processing by higher brain centers. Three local feedback systems which reside in the brainstem have been identified. These are: (1) the system controlling the middle ear muscles, including pathways subserving the middle ear muscle reflex; (2) the system which projects from the superior olive to both the cochlea and cochlear nuclei, the so-called olivo-cochlear system; and (3) the system which projects from the superior olive exclusively to the cochlear nuclei. The cells which give rise to the latter two systems are scattered in groups called peri-olivary nuclei (PON), which surround the principal cell groups of the superior olive. Cells of the PON receive direct projections from the cochlear nuclei, and project to diverse auditory brainstem nuclei. One cell group, the lateral nucleus of the trapezoid body (LNTB), consists of cells which project heavily to the ipsilateral cochlear nucleus. Therefore, the LNTB represents a well segregated part of the local feedback to the cochlear nuclei and has a relatively simple organization. This project is a focused study of the LNTB and may reveal principles which can aid in understanding the roles of other descending projections to the cochlear nuclei. A description of the extent to which the LNTB is influenced by input from the cochlear nuclei, as opposed to inputs from higher brain centers, will be the aim of many experiments in this proposal. The experiments are guided by the hypothesis that feedback projections play a role in preserving the representations of sound in the presence of noisy backgrounds, and can work by the mechanism of affecting lateral inhibition of cells of the cochlear nuclei. The experiments are divided into two groups. The first group of experiments is designed to determine the anatomical organization and physiological properties of LNTB neurons. The second group of experiments test the hypothesis of LNTB function. The proposed experiments use a combination of in vitro (brain slice) and in vivo electrophysiological and anatomical techniques that are already in use in the laboratory. The combination of preparations will bring greater experimental control and flexibility to bear on investigation of LNTB functions and mechanisms. These experiments may reveal neural mechanisms of signal extraction in a noisy background, which may also provide information important for improving designs of prosthetic devices that replace nonfunctioning parts of the auditory nervous system.

该项目的目的是了解本地反馈的作用 在塑造人工耳蜗核的系统 较高大脑中心处理的声音。 三个本地反馈系统 已经确定了存在于脑干中的。 这些是：（1） 控制中耳肌肉的系统，包括途径下降 中耳肌肉反射； （2）从 上橄榄与耳蜗和耳蜗核，所谓的 Olivo-Cochlear系统； （3）从上级投射的系统 橄榄专门针对人工耳蜗。 产生的细胞 后两个系统分散在称为杀生核的组中 （PON），围绕上橄榄的主要细胞基团。 PON的细胞接收来自耳蜗核的直接投影，并且 项目对不同听觉的脑干核。 一个细胞组，侧面 梯形体（LNTB）的核由投射的细胞组成 大量到同侧耳蜗核。 因此，LNTB 代表了对人工耳蜗的本地反馈的隔离部分 核，具有相对简单的组织。 这个项目是一个重点 研究LNTB，可能会揭示可以有助于理解的原则 其他下降投影对耳蜗核的作用。 一个 描述LNTB受到的输入影响的程度 耳蜗核与高脑中心的输入相反，将是 该提案中许多实验的目的。 实验以反馈预测播放的假设为指导 在嘈杂的情况下保存声音的表现方面的作用 背景，可以通过影响横向抑制的机制起作用 人工耳蜗细胞的细胞。 实验分为两个 组。 第一组实验旨在确定 LNTB神经元的解剖组织和生理特性。 这 第二组实验检验了LNTB功能的假设。 这 拟议的实验结合了体外（脑切片）和 已经正在使用的体内电生理和解剖技术 在实验室。 准备工作的组合将带来更大的 实验控制和灵活性，以对LNTB进行研究 功能和机制。 这些实验可能揭示了神经机制 在嘈杂的背景下的信号提取，这也可能提供 信息对于改善假肢设计的设计很重要 更换听觉神经系统的无功能部分。