MORPHOMETRY OF IDENTIFIED TERMINALS IN COCHLEAR NULEUS

耳蜗核中已识别终端的形态学

• 批准号: 2127209
• 负责人: ALICE M BERGLUND
• 金额: $ 4.1万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-04-01 至 1996-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2127209
• 关键词: auditory nuclei; cell type; electron microscopy; image processing; morphology; nerve endings; neuroanatomy; neurons; synapses

The long-range objective of this project is to understand the synaptic organization of the cochlear nucleus (CN), where auditory signals first reach the brain. Auditory nerve input reaches the CN in a tonotopically organized manner, where all fibers terminate and synapse with various CN cell types. This primary inputs is not homogeneous. Physiological recordings have indicated that it comprises 3 groups distinguishable by spontaneous discharge rates (SR; Liberman, 78). These groups of high, medium, and low-SR have been correlated with the distribution and morphology of fibers and terminals both peripherally in he cochlea and centrally in the CN (e.g., Liberman, 82; Ryugo and Rouiller, 88). In order to understand the input-output functions of the CN, it is important to determine the ratios of input from the various SR classes to the different CN cell types. Given that morphological analysis. Then morphometric criteria established in this way would identify these synaptic terminals in single electron micrographs--without the need for laborious labeling and serial-section reconstruction procedures. The present proposal will specifically analyze terminals of auditory nerve fibers of known physiology, which have been intracellularly labeled with horseradish peroxidase (HRP) (tissue supplied by M.C. Liberman). Therefore, single fibers can be reconstructed and many terminals throughout the CN are available for morphometric examination. Automated measurements of selected features of these terminals (vesicle size and roundness, vesicle and mitochondrial densities, synaptic length, etc.) will be conducted to rapidly build a quantitative data base of the identifiable morphometric features of the 3 SR groups. Thus far, preliminary results demonstrate that one criterion, the size of synaptic vesicles, apparently differs in terminals of high and low SR. Morphometric features will also be related to the different classes of postsynaptic CN neurons that receive this input. After building up a comprehensive morphological data base from identified and labeled terminals, unlabeled material will be examined on the basis of these criteria in order to determine ratios of input from the physiological classes to various CN cell types.

该项目的长期目标是了解突触 耳蜗核（CN）的组织，首先是听觉信号 到达大脑。 听觉神经输入以音调方式到达 CN 有组织的方式，其中所有纤维终止并具有各种 CN 的突触 细胞类型。 这种主要投入并不是同质的。 生理 录音表明它由 3 个组组成，可通过以下方式区分： 自发放电率（SR；Liberman，78）。 这些群体的高、 中、低 SR 与分布相关 耳蜗外围纤维和末端的形态 集中在 CN（例如，Liberman，82；Ryugo 和 Rouiller，88）。 在 为了理解 CN 的输入输出功能，重要的是 确定各个 SR 类别的输入与 不同的 CN 细胞类型。 给出形态学分析。 然后 以这种方式建立的形态测量标准将识别这些 单电子显微照片中的突触末端——无需 费力的标记和连续切片重建程序。 这 本提案将具体分析听觉神经末梢 已知生理学的纤维，已在细胞内标记 辣根过氧化物酶 (HRP)（组织由 M.C. Liberman 提供）。 因此可以重构单纤、多终端 整个 CN 均可用于形态测量检查。 自动化 测量这些终端的选定特征（囊泡大小和 圆度、囊泡和线粒体密度、突触长度等） 将快速建立定量数据库 3 个 SR 组的可识别形态特征。 到目前为止， 初步结果表明，一个标准是突触的大小 囊泡，高 SR 和低 SR 的末端明显不同。 形态特征也将与不同类别的 接收此输入的突触后 CN 神经元。 建立了一个 来自识别和标记的综合形态数据库 终端，未贴标签的材料将根据这些进行检查 标准以确定生理输入的比率 各种 CN 细胞类型的类别。