PHYSIOLOGICAL DEVELOPMENT OF THE OLIVOCOCHLEAR SYSTEM

橄榄耳蜗系统的生理发育

• 批准号: 6564036
• 负责人: Edward J Walsh
• 金额: $ 26.25万
• 依托单位: FATHER FLANAGAN'S BOYS' HOME
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2003-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6564036
• 关键词: acoustic nerve; cats; cochlea; denervation; developmental neurobiology; ear hair cell; efferent nerve; electron microscopy; innervation; neuroanatomy; neurogenesis; olivocochlear bundle; organ of Corti; otoacoustic emission; vertebrate embryology

In this project, the role of the olivocochlear bundle (OCB) will be explored in multiple studies of peripheral auditory development. The finding the peripheral auditory function in animals reared in the absence of the OCB is decidedly pathological suggests that the OCB plays a role in cochlear development. However, an alternative possibility is that animals that lose their OCB early in life are highly susceptible to acoustic trauma. In proposed experiments, the peripheral auditory consequences of rearing animals deefferented at birth in a quiet environment will be studied, in addition to deefferented animals exposed to noise in an attempt to determine the source of the cochlear pathology associated with OCB transection. Auditory nerve pathology produced by such lesions is consistent with the malfunction, or abnormal expression, of the cochlear amplifier. Auditory nerve fibers from adults deefferented at birth exhibit elevated thresholds, relatively broad tuning, low spontaneous discharge rages and poor tip-totail rations. Peripheral auditory nonlinearity in animals lesioned as neonates will be assessed to test the hypothesis that OCB interactions with outer hair cells (OHCs) are required for the normal expression of active hypothesis that OCB interactions with outer hair cells (OHCs) are required for the normal expression of active cochlear mechanics. A separate experiment will test the hypothesis that the OCB plays a role in the refinement of exuberant synapses between inner hair cells and auditory nerve dendrites that occurs during development. While the proposed experiments will focus primarily on peripheral auditory pathology generated by early deefferentation, OCB development, per se, will continue to be explored. This will be done by determining the role of OHCs in the OCB-IHC detachment and intracochlear migration dynamic that occurs early in feline life, by destroying OHCs prior to the onset of hearing and anatomically evaluating the disposition of OCB terminals within the organ of Corti in physiologically characterized animals. Finally, the gap in our understanding of structure/function aspects of OCB development will be filled by studying its cochlear innervation histologically and ultrastructurally in physiologically characterized animals.

在这个项目中，橄榄石束的作用（OCB）将是 在周围听觉发展的多个研究中探讨了。 这 在饲养的动物中找到外围听觉功能 OCB的缺乏绝对是病理学表明OCB发挥 在人工耳蜗发展中的作用。 但是，另一种可能性是 生命早期失去OCB的动物非常容易受到影响 发生声学创伤。 在提议的实验中，外围听觉 饲养动物在出生时的后果 除了暴露的动物外，还将研究环境 噪声试图确定人工耳蜗病理的来源 与OCB横向相关。 听觉神经病理学由 这种病变与故障或异常表达一致 人工耳蜗放大器。 成人的听觉神经纤维 出生时表现出升高的阈值，相对较宽 调整，自发放电狂暴和尖端尾部口粮不良。 作为新生儿的动物的外围听觉非线性将 评估以检验OCB与外发相互作用的假设 细胞（OHC）是正常表达活性假设所必需的 OCB与外毛细胞（OHC）的相互作用是需要的 主动人工耳蜗的正常表达。 单独的实验 将检验OCB在完善中发挥作用的假设 内毛细胞和听觉神经树突之间的旺盛突触 这是在开发过程中发生的。 而拟议的实验将 主要专注于早期产生的外围听觉病理 Deefferentation，OCB开发本身将继续探索。 这将通过确定OHC在OCB-IHC中的作用来完成 出现在早期 猫的生活，通过在听证会开始之前销毁OHC和 解剖学评估OCB终端的处置 生理特征动物中皮尔蒂的器官。 最后， 我们对OCB结构/功能方面的理解差距 通过研究其人工耳蜗神经将填补发展 在生理特征上在组织学和超结构上 动物。