EFFERENT INFLUENCE--COCHLEAR MECHANOELECTRIC PHYSIOLOGY

传出影响--耳蜗机电生理学

• 批准号: 2654404
• 负责人: ALFRED L NUTTALL
• 金额: $ 44.38万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-04-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2654404
• 关键词: biomechanics; cell motility; cochlea; cochlear microphonic potentials; ear hair cell; efferent nerve; electrostimulus; guinea pigs; inferior colliculus; interferometry; mechanical stress; neurophysiology; neurotransmitters; nitric oxide; olivocochlear bundle

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.

声音刺激耳蜗会导致大鼠的机械电活动。 科尔蒂风琴。外毛细胞发挥中枢作用，但知之甚少 在正常的耳蜗声反应中起作用。此外，外毛细胞 (OHC)活动是由一种几乎完全未知的方式控制的 来自橄榄耳蜗传出纤维的复杂神经支配。这项建议 试图通过研究来增加我们对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反应器官将被测量为总耳蜗数 电位、耳道耳声反应、毛发感受器电位 细胞，最重要的是速度和位移响应 从科尔蒂岛的不同位置测量。这其中的每一个 测量提供了关于内部性能的不同观点 以及在活体内共同作用的神经细胞。 这项提议将一项戏剧性的新技术应用于细胞研究 内耳的震动。激光反馈干涉术是一种 具有足够灵敏度的方法来记录近几年的振动 透明的细胞元素。通过显微镜进行LFI可以让一个人 将激光聚焦在器官中不同的细胞结构上 科尔蒂的。对行波的详细研究将提供一个重要的 科尔提功能器官的理论研究的经验基础 提供有关其细胞的机械位移的信息 结构。这种理解是必要的，以便确定如何 机械能刺激内层和外层细胞。LFI显微镜可以 提供所需的细胞位移测量，以确定 在这个系统中，OHC起着能动的作用。 该提案还将研究橄榄耳蜗神经传出的生理学。 系统并确定传出神经的激活是否改变 毛细胞的力学特性。下行传出神经的生理学 系统来自下丘是作为一种方式引起的 内侧和外侧传出系统的激活 地形图载人 最后，有了这个建议，我们开始了生理学的研究 科尔蒂器官的支持细胞。直到最近才支持 细胞被认为在很大程度上是被动的元素，只有借出结构 对系统的支持。现在有越来越多的证据表明Deiters的细胞 是运动的和动态的结构。我们将测量脏器的变化。 Corti振动跟随导致变化的刺激类型 Deiters的细胞形态。 综上所述，对这项提案的研究将提供一种理解 关于：OHC如何产生高频率选择性和灵敏度 正常内耳；橄榄耳蜗传出系统和 Corti器官中支持细胞的结构动力学。