EFFERENT INFLUENCE--COCHLEAR MECHANOELECTRIC PHYSIOLOGY

描述：(改编自申请者摘要。)这项提议旨在 通过对Corti器官功能的研究，加深对其功能的认识 机械电学对声音的反应使用四种不同的、但相互关联的 测量方法：粗大耳蜗电、耳道耳声 反应、细胞内毛细胞受体电位和MOST 重要的是，基底膜的运动。其中每一项都提供了不同的 关于内、外毛细胞性能的观点。 首先将研究基底膜的详细运动模式， 使用一种新的方法来达到这个目的。一种新的、详细的视角 行波模式将为未来提供重要的经验基础 Corti器官功能的理论模型和建立的观点 测量橄榄耳蜗传出活动的实验偏离。 自然的，声音唤起的，传出的以及电的激活 将对激活进行研究。传出时耳道的耳声变化 将激活情况直接与基底膜运动变化进行比较。 这一比较将揭示神经控制的一些机械方面 外毛细胞表现。传出系统的保护作用 我们将研究巨大声音的破坏性影响，以及如何 传出活动可以提高我们检测和编码声音的能力 存在掩蔽性的噪音。 研究人员还将研究高等脑干的生理学。 下行传出通路的水平。电流刺激 下丘的区域将被用来激活这个系统， 不仅带来了关于下行路径的新信息，而且 也可能是关于“外侧”传出纤维的未知生理学。 它们终止于传入神经元的外周突起。

DESCRIPTION: (Adapted from the Applicants' Abstract.) This proposal seeks to add to our knowledge concerning organ of Corti function by examining its mechanoelectric responses to sound using four distinct, but linked measurement approaches; gross cochlear potentials, ear canal otoacoustic responses, intracellular hair cell receptor potentials, and most importantly, basilar membrane motion. Each of these provides a different viewpoint on the performance of inner and outer hair cells. The detailed motion pattern of the basilar membrane will be studied first, using a new method for this purpose. A new and detailed view of the traveling wave pattern will provide an important empirical base for future theoretical models of the organ of Corti function and establish a point of experimental departure to measure olivocochlear efferent activity. Natural, sound evoked, activation of efferents as well as electrical activation will be studied. Ear canal otoacoustic changes during efferent activation will be directly compared to basilar membrane motion changes. This comparison will reveal some mechanical aspects of neurally controlled outer hair cell performance. The role of the efferent system to protect OHCs from the damaging effects of loud sound will be studied, as will how efferent activity can improve our ability to detect and code sounds in the presence of masking noises. The investigators will also study the physiology of the higher brain stem levels of the descending efferent pathways. Electric current stimulation of areas of the inferior colliculus will be used to activate this system, leading not only to new information on the descending pathways proper but perhaps also on the unknown physiology of the "lateral" efferent fibers which terminate on the peripheral processes of afferent neurons.