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。本应用是扩展一套新的使用扫描激光干涉仪测量耳蜗机械反应的方法，以解决以下基本问题：(1)在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怎样的？(3) BM振动的空频关系是什么？(4)敏感耳蜗是否存在共振机制？具体目的一是测量敏感沙鼠耳蜗BM振动的纵向范围和波长。假设在低强度和中等强度下，耳蜗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目前有关耳蜗放大器位置和耳蜗非线性机理的理论提供量化参数。具体目标二将测量BM振动的大小和相位作为径向位置的函数。假设有一个显著的相位变化跨越BM宽度将被测试。本实验将验证外毛细胞（OHC）产生的力与被动BM振动之间的假定时间关系。具体目标三将测量BM振动在不同频率和强度下的纵向模式。通过将空间数据与从单个BM位置测量的调谐曲线进行比较，将检验尖锐调谐是BM振动空间受限纵向模式的频率表示的假设。本实验的结果将对验证耳蜗尺度对称的基本理论至关重要。专项目的四将探讨耳蜗共振机制。BM作为共振系统响应局部刺激的假设将通过测量BM对局部光声刺激的响应来验证。本研究的信息将加强听力学测试的临床解释，并为听力损失的康复提供人工听力的新方法。

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.