STRUCTURE AND FUNCTION OF PARALLEL AUDITORY PATHWAYS

平行听觉通路的结构和功能

• 批准号: 6104418
• 负责人: DOUGLAS L OLIVER
• 金额: $ 14.4万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6104418
• 关键词: auditory nuclei; auditory pathways; auditory stimulus; cell type; central neural pathway /tract; cochlea; electron microscopy; immunocytochemistry; inferior colliculus; laboratory rabbit; neural information processing; neuroanatomy; neurons; psychoacoustics; auditory nuclei; auditory pathways; auditory stimulus; cell type; central neural pathway /tract; cochlea; electron microscopy; immunocytochemistry; inferior colliculus; laboratory rabbit; neural information processing; neuroanatomy; neurons; psychoacoustics

This project will address the organization of neurons into parallel pathways within the central auditory system. While the anatomical evidence for parallel circuitry in the auditory system is compelling, the functional consequences of this circuitry are not known. This study will elucidate the role of this circuitry in central auditory processing. Neurons in the auditory system can be classified according to their binaural response properties. Monaural neurons respond only to sounds presented in one ear. Binaural neurons can be effected by sounds delivered to both ears. Both types of neuron may be involved in a variety of auditory functions, but some behaviors, like sound localization, may emphasize one class of neuron over another. Monaural and binaural neurons can be found at all levels of the auditory system, but, the anatomical cell types and circuits related to these responses are not certain. We hypothesize that cells which respond only to monaural stimulation are synaptically connected to form one or more monaural circuits. These monaural circuits would be distinct from circuits concerned with binaural processing. In the present proposal, we will focus on the neurons with monaural response features in the lower brain stem. The cochlear nucleus (CN) and ventral nucleus of the lateral lemniscus (VNLL) are major centers with monaural neurons, and both project to the inferior colliculus (IC). Despite the importance of these structures for understanding monaural responses in the IC and in higher centers, critical data are still lacking on the cells involved in these projections. Therefore, AIM 1 is to determine which cell types participate in the CN-VNLL-IC circuit and compare them to the cells involved in the CN-IC circuit. Axonal transport labeling in vivo and intracellular injections in fixed brain slices will be used. We predict that different cell types will participate in each circuit. Double-labeling experiments will determine if the same neurons in the CN project to both the VNLL and IC. Finally, anterograde transport and intracellular experiments will determine the nature of the synaptic connections made in the VNLL by axons from the CN. We anticipate that specific synaptic arrangements will characterize the neuropil of the VNLL. The monaural responses in VNLL are attributed to strong inputs from the contralateral CN and a dearth of inputs from the superior olivary complex. There is little physiological data on the VNLL to confirm its monaural properties in terrestrial mammals. Therefore, AIM 2 is to characterize the response properties of units in the VNLL of the awake rabbit. We anticipate that most cells in VNLL will be monaural; however, their responses may be different from those in the CN.

该项目将平行解决神经元的组织 中央听觉系统中的途径。 而解剖学 听觉系统中平行电路的证据令人信服， 该电路的功能后果尚不清楚。 这项研究会 阐明该电路在中央听觉处理中的作用。 听觉系统中的神经元可以根据其分类 双耳响应特性。 单膜神经元只对声音做出反应 呈现在一只耳朵中。 双耳神经元可以通过声音影响 送到两个耳朵。 两种类型的神经元可能都参与 多种听觉功能，但是某些行为，例如声音 本地化可能会强调一类神经元而不是另一种神经元。 单声道 在听觉系统的各个级别可以找到双耳神经元， 但是，与这些响应有关的解剖细胞类型和电路 不确定。 我们假设仅响应的细胞 单声刺激在突触上连接以形成一个或多个 单膜电路。 这些单声道电路将与 与双耳处理有关的电路。 在本提案中，我们将重点关注具有单膜的神经元 下脑茎中的反应特征。 耳蜗核（CN）和 外侧Lemniscus（VNLL）的腹侧核是主要中心 单膜神经元，并且都投射到下丘（IC）。 尽管这些结构对于理解单声道很重要 IC和高级中心中的响应，关键数据仍在 缺乏这些投影所涉及的细胞。 因此，目标1是 确定哪种细胞类型参与CN-VNLL-IC电路，并 将它们与CN-IC电路所涉及的单元进行比较。 轴突 在体内和细胞内注射固定脑的转运标记 将使用切片。 我们预测不同的细胞类型将 参加每个电路。 双标签实验将确定 如果CN项目中的VNLL和IC都具有相同的神经元。 最后， 顺行传输和细胞内实验将确定 CN中轴突在VNLL中产生的突触连接的性质。 我们预计特定的突触安排将表征 vnll的神经胶体。 VNLL中的单声响应归因于来自 对侧CN和上级橄榄所缺乏的投入 复杂的。 VNLL几乎没有生理数据来确认其 陆生哺乳动物的单膜特性。 因此，目标2是 表征醒着的vnll中单元的响应属性 兔子。 我们预计VNLL中的大多数细胞将是单声道。然而， 他们的反应可能与CN中的反应不同。