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.

该项目的远程目标是了解突触 耳蜗核组织（CN）的组织，听觉信号首先 到达大脑。 听觉神经输入以体积量的方式到达CN 有组织的方式，所有纤维用各种CN终止和突触 细胞类型。 此主要输入不是均匀的。 生理 录音表明，它包括3组可区分的组 自发放电率（SR； Liberman，78）。 这些群体 培养基和低-SR与分布相关 纤维和终端的形态既在He耳蜗中都有外围 中央位于CN（例如Liberman，82； Ryugo和Rouiller，88）。 在 为了了解CN的输入输出功能，这很重要 确定从各个SR类与的输入之比 不同的CN细胞类型。 鉴于形态学分析。 然后 以这种方式建立的形态计量标准将确定这些标准 单电子显微照片中的突触终端 - 不需要 费力的标签和串行部分重建程序。 这 目前的建议将专门分析听觉神经的终端 已知生理学的纤维，已在细胞内标记 辣根过氧化物酶（HRP）（由M.C. Liberman提供的组织）。 因此，可以重建单个纤维和许多端子 在整个CN中，可用于形态计量学检查。 自动化 测量这些终端选定特征（囊泡大小和 圆度，囊泡和线粒体密度，突触长度等） 将进行迅速建立一个定量数据库 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，突触的大小 囊泡，显然在高和低SR的末端有所不同。 形态计量特征也将与不同类别的类别有关 接收此输入的突触后CN神经元。 建立一个 鉴定和标记的全面形态数据库 终端，未标记的材料将根据这些材料进行检查 标准以确定生理的输入比率 各种CN细胞类型的类。