BIOLOGICAL CONSTRAINTS ON TUNING IN THE INNER EAR

拟议研究的总体目标是更丰富地了解 频率选择性的结构和生理基础 脊椎动物的听觉系统。特别是，该计划的主要目标是 建议的研究是为了了解和欣赏 频率分辨率背后的机械和电气因素 脊椎动物的听觉系统，并提供对 影响调谐的刺激相互作用的潜在机制 脊椎动物的内耳。为了实现第一个目标，我们打算 进行一系列三项详细调查，以便(A)直接 测量覆盖膜隔板的运动响应于 并因此更准确地定义了该结构在 频率分析，(B)现场表征温度依赖性 覆盖膜分区对纯音的响应，以及(C) 系统研究解剖学定义的毛发的膜特性 两栖动物乳头中的细胞，并将这些特性与 器官的已知音调组织。要实现第二个目标 目标，我们将(D)扩展我们对相互作用的研究 声学和地震刺激对新近表征的双峰的影响 第八神经中的纤维，和(E)量化的程度 通向内耳的鼓外通路在塑造被调谐的人方面发挥着作用 外周听觉系统的反应。我们认为，这些数据 这种结构-功能和尿道学相结合的方法的结果 将具有丰富的关于解剖学和神经基础的含义 是处理复杂声音的基础，这项工作将有助于 作为理解人类语音基本问题的模型 在嘈杂环境中的感知。

The overall goal of the proposed research is a richer understanding of the structural and physiological bases of frequency selectivity in the vertebrate auditory system. In particular, the primary objectives of the proposed research are to gain an understanding and appreciation of the mechanical and electrical factors underlying frequency resolution in the vertebrate auditory system, and to provide further insights into the mechanisms underlying stimulus interactions which affect tuning in the vertebrate inner ear. To accomplish the first objective, we intend to perform a series of three detailed investigations in order to (a) directly measure the motion of the tectorial membrane partition in response to sound and thus more precisely define the role of this structure in frequency analysis, (b) characterize in situ the temperature dependence of the tectorial membrane partition in its response to pure tones, and (c) systematically study the membrane properties of anatomically-defined hair cells from the amphibian papilla, and to relate these properties to the known tonotopic organization of the organ. To accomplish the second objective, we shall (d) extend our investigation of the interactions between acoustic and seismic stimuli on the recently characterized bimodal fibers in the eighth nerve, and (e) quantify the extent to which the extratympanic pathways to the inner ear play a role in sculpting the tuned responses of the peripheral auditory system. We believe that the data that result from this combined structure-function and neurethological approach will be rich in implications regarding the anatomical and neural substrate underlying the processing of complex sounds, and that this work will serve as a model for understanding fundamental problems of human speech perception in noisy environments.