Experimental study of the cochlear amplifier

描述（由申请人提供）：本实验室的长期目标是实验研究耳蜗功能的机械机制。本申请是使用扫描激光干涉仪来扩展耳蜗机械响应的一组新的测量，以解决以下基本问题：（1）敏感耳蜗中行波的纵向范围和实际波长是什么？(2)BM在径向上的振动模式是什么？(3)BM振动的空间频率关系是什么？(4)在敏感的耳蜗中是否可以通过实验证明共振机制？具体目标一是测量敏感的沙鼠耳蜗BM振动的纵向幅度和波长。假设是在低强度和中等强度下，BM振动的纵向范围和耳蜗行波的波长比以前认为的要小得多。本实验的数据将为验证耳蜗放大器的位置和耳蜗非线性机制的现有理论提供量化参数。具体目标二将测量作为径向位置的函数的BM振动的幅度和相位。将检验跨BM宽度存在显著相位变化的假设。本实验将验证外毛细胞（OHC）产生的力和被动BM振动之间的假定的时间关系。具体目标三将测量不同频率和强度下BM振动的纵向模式。将通过将空间数据与从单个BM位置测得的调谐曲线进行比较来检验锐调谐是BM振动的空间受限纵向模式的频率表示的假设。这个实验的结果对于检验耳蜗标度对称性的基本理论是至关重要的。具体目的四是探讨耳蜗共振机制。将通过测量BM对局部光声刺激的响应来测试BM作为共振系统响应局部刺激的假设。这项研究的信息将提高听力学测试的临床解释，并提出新的方法，人工听力康复听力损失。

DESCRIPTION (provided by applicant): The long-term objective of this laboratory is to experimentally study the mechanical mechanisms of cochlear functions. This application is to extend a novel set of measurements of cochlear mechanical responses using a scanning laser interferometer to address the following fundamental questions: (1) What are the longitudinal extent and the actual wavelength of the traveling wave in the sensitive cochlea? (2) What is the vibration pattern of the BM in the radial direction? (3) What is the space-frequency relationship of BM vibration? (4) Can a resonance mechanism be demonstrated experimentally in the sensitive cochlea? Specific aim one will measure the longitudinal extent and the wavelength of BM vibration in sensitive gerbil cochleae. The hypothesis is that at low and intermediate intensities, the longitudinal extent of the BM vibration and the wavelength of the cochlear traveling wave are much smaller than previously thought. The data from this experiment will provide quantified parameters for testing current theories on the location of the cochlear amplifier and the mechanism of cochlear nonlinearity. Specific aim two will measure the magnitude and phase of BM vibration as a function of the radial location. The hypothesis that there is a significant phase variation across the BM width will be tested. This experiment will verify the putative temporal relationship between the outer hair cell (OHC)-generated force and the passive BM vibration. Specific aim three will measure the longitudinal patterns of BM vibrations at different frequencies and intensities. The hypothesis that the sharp tuning is a frequency representation of the spatially restricted longitudinal pattern of BM vibration will be tested by comparing the spatial data to the tuning curve measured from a single BM location. Results from this experiment will be critical for testing the fundamental theory of cochlear scaling symmetry. Specific aim four will investigate the cochlear resonance mechanism. The hypothesis that the BM responds to local stimulation as a resonant system will be tested by measuring BM responses to a local photoacoustic stimulation. The information from this study will enhance clinical interpretation of audiological tests and suggest new approaches for artificial hearing for rehabilitating hearing loss.