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， 建议的研究是为了了解和欣赏 机械和电气因素下的频率分辨率在 脊椎动物的听觉系统，并提供进一步的见解， 刺激相互作用的潜在机制，影响调谐 脊椎动物的内耳。为了实现第一个目标，我们打算 进行一系列的三个详细调查，以便（a）直接 测量顶盖膜分区响应于 声音，从而更准确地定义了这种结构的作用， 频率分析，（B）原位表征温度依赖性， 在其对纯音的反应中的盖膜分区，以及（c） 系统地研究了解剖学定义的毛发的膜特性， 细胞从两栖类乳头，并将这些属性与 已知的器官的音调组织。为了完成第二个 目标，我们将（d）扩大我们的相互作用的调查 在最近表征的双峰上的声学和地震刺激之间 在第八神经纤维，和（e）量化的程度， 到内耳的鼓室外通路在塑造调谐的 周边听觉系统的反应。我们认为， 从结构-功能和神经组织学的角度 将在解剖学和神经基础方面有丰富的意义 复杂声音处理的基础，这项工作将服务于 作为理解人类语言基本问题的模型 噪音环境中的感知。

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.