OLIVOCOCHLEAR EFFERENT SYSTEMS

描述(调查人员摘要)：调查人员提出了一系列 以解决许多理论上重要的问题 利用内侧神经的作用研究完整耳蜗区的细胞相互作用 作为一种工具的橄榄耳蜗神经传出。一个次要目标是理解 由听神经中刺激编码的传出产生的变化。 所获得的数据应提供与此相关的重要新见解 问题是：是什么事件控制了听神经纤维的放电？ 传出活动是否部分通过改变耳蜗腔起作用？ 潜力？是什么因素使听神经纤维的高反应性 自发放电率与低自发放电率不同？ 传出神经引起听神经纤维放电的什么变化 当声音远高于阈值且不在光纤上时的活动 特征频率(CF)？双音抑制是如何产生的？ 传出活动是如何影响它的？耳声发射是怎样的？ 以及传出活动如何影响它们？时间过得怎么样？ 各种传出效应的过程相互关联，并与 导致这些影响的潜在传出行为？有多大 是单一传出纤维对听神经反应的影响，以及 这些影响是如何相加的？ 调查人员将通过以下方式解决这些问题：比较 不同SIRS对听神经纤维的传出诱发效应 来自同一个CAT的相同的CF值，2：同时测量机械和神经 双音抑制的效果及其与传统双音抑制的比较 传出刺激。3.测量内侧传出神经的时程 对一连串电击的反应(机械、电气和神经)， 以及4.确定中间的数目之间的对应关系 火产生的传出物质和产生的影响。耳蜗术后的变化 将通过测量刺激频率的变化来监控力学 发射和传出诱发的电变化将由 测量耳蜗内电位的变化。

DESCRIPTION (Investigator's Abstract): The investigators propose a series of measurements to address many theoretically important issues at the level of cellular interactions in the intact cochlea using the action of medial olivocochlear efferents as a tool. A subsidiary goal is to understand the changes produced by efferents in stimulus coding in the auditory nerve. The data obtained should provide significant new insights relevant to such questions as: What events control the firing of auditory-nerve fibers? Does efferent activity act in part through a change in endocochlear potential? What factors make responses of auditory-nerve fibers with high spontaneous firing rates different from those with low spontaneous rates? What changes in firings of auditory-nerve fibers are produced by efferent activity when sounds are well above threshold and not at the fiber characteristic frequency (CF)? How is two-tone suppression produced, and how is it influenced by efferent activity? How are otacoustic emissions generated, and how does efferent activity affect them? How do the time courses of various efferent effects relate to one another and to the underlying efferent actions which give rise to these effects? How large are the effects of a single efferent fiber on auditory-nerve responses, and how do these effects summate? The investigators will address these questions by 1: comparing efferent-evoked effects on auditory-nerve fibers with different Sirs but the same CF from the same cat, 2: measuring both mechanical and neural effect of two-tone suppression and comparing these effects with those efferent stimulation. 3: measuring the time courses of medial-efferent effects (mechanical, electrical and neural) in response to trains of shock, and 4. determining the correspondence between the number of medial efferents that fire and the effects produced. Changes in cochlear mechanics will be monitored by measuring changes in stimulus frequency emissions and efferent-evoked electrical changes will be monitored by measuring changes in endocochlear potential.