EFFERENT INFLUENCE--COCHLEAR MECHANOELECTRIC PHYSIOLOGY

耳蜗的声音刺激导致耳蜗中的机械电活动。 Corti器官 外毛细胞在中枢神经系统中起着重要作用， 在正常耳蜗对声音的反应中的作用。此外，外毛细胞 (OHC)活动以一种几乎完全未知的方式被一种 橄榄耳蜗传出纤维的复杂神经支配。这项建议 试图通过检查来增加我们对Corti器官功能的理解 它对声音和传出神经电的机械电反应 刺激. Corti器官反应将被测量为大体耳蜗反应。 电位，耳道耳声反应，毛发感受电位 细胞，最重要的是作为速度和位移响应 从Corti或an的各个位置测量。这一切成功都 测量提供了一个不同的观点对性能的内部 和OHC在体内共同作用。 这项提议为研究细胞生物学提供了一项引人注目的新技术。 内耳的振动。激光反馈干涉测量（LFI）是一种 方法具有足够的灵敏度，以记录振动近 透明的细胞元素。通过显微镜应用LFI， 将激光束聚焦到器官的不同细胞结构上 关于Corti对行波的详细研究将提供一个重要的 为Corti器功能理论研究提供了实验基础 提供关于其细胞的机械位移的信息， 结构.这种理解是必要的，以确定如何 机械能刺激内部和OHC。LFI显微镜可以 提供所需的细胞位移测量，以确定 OHC在这个系统中起着能动的作用。 该计划还将研究橄榄耳蜗传出神经的生理学 系统，并确定传出神经的激活是否改变了 OHC的机械性能。下行传出神经的生理学 系统从下丘被列入作为一种方式， 激活的内侧和外侧传出系统在一个 地形载人 最后，通过这个建议，我们开始了对生理学的研究。 Corti器官的支持细胞。直到最近， 细胞被认为是主要的被动元素， 支持系统。现在有越来越多的证据表明，迪特斯的细胞 是能动的动态结构。我们将测量器官的变化 Corti振动以下类型的刺激，导致的变化， 迪特斯的细胞形态 对这一建议的研究将提供一种理解， OHC如何产生高频率选择性和灵敏度 正常内耳;橄榄耳蜗传出系统的功能， Corti器官中支持细胞的结构动力学。

Sound stimulation of the cochlea leads to mechanoelectric activity in the organ of Corti. Outer hair cells play a central but little understood role in the normal cochlea response to sound. Furthermore, outer hair cell (OHC) activity is controlled in an almost completely unknown way by a complex innervation from the olivocochlear efferent fibers. This proposal seeks to add to our understanding of organ of Corti function by examining its mechanoelectric responses to sound and to efferent nerve electric stimulation. Organ of Corti responses will be measured as gross cochlear potentials, ear canal otoacoustic responses, receptor potentials of hair cells, and most importantly as velocity and displacement responses measured from various locations in the or an of Corti. Each of these measurements provides a different viewpoint on the performance of inner and OHCs acting together in vivo. This proposal applies a dramatic new technology for the study of cellular vibration in the inner ear. Laser feedback interferometry (LFI) is a method with sufficient sensitivity to register the vibration of nearly transparent cellular elements. LFI applied through a microscope allows one to focus a laser beam onto the different cellular structures in the organ of Corti. A detailed study of the traveling wave will provide an important empirical base for theoretical studies of organ of Corti function by providing information on mechanical displacements of its cellular structures. This understanding is necessary in order to determine how mechanical energy stimulates the inner and OHCs. LFI microscopy can provide the cellular displacement measurements needed to determine how OHCs serve as motile elements in this system. The proposal will also study the physiology of the olivocochlear efferent system and determine whether activation of the efferent nerves changes the mechanical properties of OHCs. The physiology of the descending efferent system from the inferior colliculus is included as a way to cause activation of both the medial and the lateral efferent systems in a topographic manned Finally, with this proposal we are beginning the study of the physiology of the supporting cells of the organ of Corti. Until recently supporting cells were thought to be largely passive elements only lending structural support to the system.There is mounting evidence now that Deiters' cells are motile and dynamic structures. We will measure the changes in organ of Corti vibration following types of stimulation that lead to changes in Deiters' cell morphology. Taken together the studies of this proposal will provide an understanding of: how OHCs generate high frequency selectivity and sensitivity in the normal inner ear; the function of the olivocochlear efferent system and the structural dynamics of supporting cells in the organ of Corti.