PHYSIOLOGICAL DEVELOPMENT OF THE OLIVOCOCHLEAR SYSTEM

在这个项目中，橄榄耳蜗束(OCB)的作用将是 在关于外周听觉发育的多项研究中进行了探索。这个 发现饲养动物的外周听觉功能 组织公民行为的缺席无疑是病态的，这表明组织公民行为在 在耳蜗发育过程中扮演的角色。然而，另一种可能性是 在生命早期失去有组织犯罪的动物非常容易受到影响 与听觉创伤有关。在拟议的实验中，周围听觉 在安静的环境中饲养动物的后果在出生时就会消失 除了暴露不同的动物外，还将对环境进行研究 以噪声来试图确定耳蜗病理学的来源 与OCB横断术相关。听神经病理所致 这种损害与功能障碍或异常表达相一致， 耳蜗扩音器。成人听神经纤维 出生时的感觉阈值升高，相对较宽 调谐，低自发放电率和较差的尖端尾部配给。 新生儿期受损动物的外周听觉非线性 被评估以检验OCB与外毛相互作用的假设 主动假设的正常表达需要细胞(OHC) OCB与外毛细胞(OHC)的相互作用是 活跃的耳蜗力学的正常表达。一项单独的实验 将检验组织公民行为在完善 内毛细胞与听神经树突之间活跃的突触 这发生在发育过程中。虽然拟议的实验将 主要关注早期所产生的外周听觉病理 此外，还将继续探索组织公民行为本身的发展。 这将通过确定OCB-IHC中OCB-IHC的作用来实现 早期发生的剥离和绒毛内迁移动力学 猫的生命，通过在听力和听力开始之前破坏内脏细胞 在解剖学上评估OCB终端在 具有生理特征的动物体内的科尔蒂器官。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 发育将通过研究其耳蜗神经来实现 生理学特征的组织学和超微结构 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.