PHYSIOLOGICAL DEVELOPMENT OF THE OLIVOCOCHLEAR SYSTEM

在这个项目中，橄榄耳蜗束（OCB）的作用将是 在多项外周听觉发育研究中进行了探索。 的 发现周围听觉功能的动物饲养在 OCB的缺失无疑是病理性的，这表明OCB 在耳蜗发育中的作用。 然而，另一种可能性是， 在生命早期失去OCB的动物 听觉创伤 在拟议的实验中，外周听觉 在一个安静的环境中饲养出生时就被遗弃的动物的后果 除了暴露的动物外，还将研究环境 以试图确定耳蜗病变的来源 与OCB横断有关。 听神经病理学由 这种损伤与功能障碍，或异常表达， 耳蜗放大器 成人的听觉神经纤维 在出生时表现出较高的阈值，相对较宽， 调谐，低自发放电率和差的tip-totail口粮。 新生儿期损伤的动物外周听觉非线性 评估OCB与外部毛发相互作用的假设 细胞（OHC）是活性假设的正常表达所必需的 OCB与外毛细胞（OHC）的相互作用是 主动耳蜗力学的正常表达。 单独的实验 将测试的假设，即组织公民行为发挥了作用，在细化 内毛细胞和听神经树突之间的旺盛突触 发生在发育过程中。 虽然拟议的实验将 主要集中在周围听觉病理产生的早期 因此，将继续探讨组织公民行为本身的发展。 这将通过确定OHC在OCB-IHC中的作用来实现 早期发生的脱离和颅内迁移动态， 猫的生命，通过破坏OHC之前的听力发作， 解剖学上评估OCB终端在 生理特征动物的Corti器官。 最后 我们对组织公民行为的结构/功能方面的理解存在差距 通过研究其耳蜗神经支配， 组织学和超微结构上， 动物

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.