OLIVOCOCHLEAR EFFERENT SYSTEMS AND COCHLEAR PHYSIOLOGY

描述：（改编自申请人的摘要）：尽管在 了解耳蜗功能的许多方面， 耳蜗微观力学是基本的， 几乎缺席。在传统观点中，基底膜运动弯曲 内毛细胞（IHC）静纤毛由一个单一的振动模式，并有 一个单一的行波沿着基底膜。然而，这种观点并不 符合我们最近的工作，表明有多个激励驱动器或 机械和神经数据显示在顶点有多组延迟。 几条线索的证据指向一个新的概念耳蜗微观力学 其中Corti器官以不同的模式振动，每个模式都有自己的共振， 频率，并且每个都为IHC静纤毛提供激励驱动。与 耳蜗分区允许以多个重叠的运动移动， 是多个行波。来自单个神经纤维的记录 揭示了多重共振，非常适合跟踪这些 沿着耳蜗共振。 建议的工作将（1）区分影响励磁驱动器， 单个神经纤维的反应，沿着耳蜗沿着映射它们，以及 确定它们的行波速度，（2）确定这些共振如何 受传出刺激和低频“偏置”音的影响，以及（3） 测试一个深刻的耳蜗非线性控制的假设， 某些模式之间的转换。 拟议的实验将检验我们初步提出的假设。 结果表明，存在两个重叠的行波。我们的结果将 提供的数据将充实耳蜗力学的新图景， 为形成新的实验提供了丰富的数据来源， 耳蜗的生物物理学和细胞生物学基础的模型 共振由于耳蜗神经纤维实验不侵犯耳蜗， 我们对存在于完整， 功能正常的耳蜗将提供一个黄金标准， 确定所见模式和任何侵入性实验的正常性。获得 在这个关键的机械水平上的总体功能特性是 对于理解外毛细胞运动和其他细胞运动 和耳蜗的结构特性产生耳蜗放大器和引线 到耳蜗的输出。

DESCRIPTION: (Adapted from applicant's abstract): Despite great progress in understanding many aspects of cochlear function, knowledge in the key area of cochlear micromechanics is rudimentary and knowledge of apical macromechanics is almost absent. In the conventional view, basilar-membrane motion bends inner-hair-cell (IHC) stereocilia by a single vibrational pattern and there is a single traveling wave along the basilar-membrane. However, this view does not fit with our recent work which shows there are multiple excitation drives or with mechanical and neural data showing multiple group delays in the apex. Several lines of evidence point to a new conception of cochlear micromechanics in which the organ of Corti vibrates in modes, each with its own resonant frequency and each providing an excitation drive to IHC stereocilia. With the cochlear partition allowed to move in multiple, overlapping motions, there can be multiple traveling waves. Recordings from single auditory-nerve fibers reveal the multiple resonances and are ideally suited for tracking these resonances along the cochlea. The proposed work will (1) distinguish the excitation drives that affects the responses of individual auditory-nerve fibers, map them along the cochlea, and determine their traveling wave velocities, (2) determine how these resonances are affected by efferent stimulation and low-frequency "bias" tones, and (3) test the hypothesis that a profound cochlear nonlinearity control the transition between certain modes. The proposed experiments will test the hypothesis suggested by our preliminary results that there ate two overlapping traveling waves. Our results will provide data that will flesh out a new picture of cochlear mechanics and provide a rich source of data for the formation of new experiments, and new models for the biophysical and cell-biological basis of the cochlear resonances. Since auditory-nerve-fiber experiment do not invade the cochlea, our characterization of the resonant modes present in an intact, normally-functioning cochlea will provide a gold standard that can be used to determine the normally of the modes seen and any invasive experiment. Obtaining an overall functional characterization at this pivotal mechanical level is essential for understanding how outer -hair-cell motility and other cellular and structure properties of the cochlea produce the cochlear amplifier and lead to output of the cochlea.