Auditory Mechanics and the Cochlear Amplifier 2020

项目摘要/摘要：听觉力学和相干放大2020 输入到耳蜗的声音引起感觉组织运动的频率分类波型， 将声音信息传递给听觉神经元，从而产生听觉。目前无法治愈的方面 听力障碍的一个重要原因是耳蜗的能力下降， 频率.耳蜗的健康频率调谐主要由耳蜗放大器提供， 外毛细胞驱动的、位置频率局部化的机电反馈机制， 强大而脆弱本项目的目标1-3是探索耳蜗放大的细胞/结构基础。 这些研究使用脑内传感器和尖端的成像和振动测量技术， 谱域光学相干断层扫描（SD-OCT）。机械性能的局部测量 耳蜗感觉组织处和内部的电反应将在健康的 正常耳蜗和改良耳蜗。沙鼠和豚鼠是使用和关键方面的耳蜗 目的2中比较了两个物种的扩增。在目标1中，测量是在 耳蜗内注射物质前后的耳蜗，这些物质将改变盖膜 (TM)力学因为它控制着毛细胞中的转导，TM在以下方面起着深远的作用： 耳蜗放大;我们的研究测试基于耳蜗模型的假设， 在分离的TM和TM突变小鼠中的测量。目的3利用SD-OCT的穿透性 测试Corti器官以前无法测试的流体力学特性的能力。Aim 4探索 声音通过中耳传输到耳蜗，以及这种传输是如何通过 来自中耳肌鼓膜张肌的反馈在初步工作中，鼓膜张肌修改 以一种微妙的、依赖于频率的方式传输， 例如，在通信过程中。鼓膜张肌紧张的实验 将决定肌肉如何影响所传输的声音信号。

Project Summary / Abstract: Auditory Mechanics and Cochlear Amplification 2020 Sound input to the cochlea causes a frequency-sorted wave-pattern of sensory tissue motion that conveys sound information to the auditory neurons, leading to hearing. A currently untreatable aspect of hearing impairment is the deterioration of the cochlea's ability to sharply separate sound by frequency. The cochlea's healthy frequency tuning is largely provided by the cochlear amplifier, an outer-hair-cell-driven, place-frequency-localized electromechanical feedback mechanism that is both powerful and fragile. This project's aims 1-3 explore the cell/structure basis of cochlear amplification. The studies use intracochlear sensors and a cutting-edge imaging and vibrometry technology, spectral-domain optical-coherence-tomography (SD-OCT). Localized measurements of mechanical and electrical responses at and within the cochlea's sensory tissue will be made both in healthy normal and in modified cochleae. Gerbils and guinea pigs are used and critical aspects of cochlear amplification are compared in the two species in aim 2. In aim 1, measurements are made in cochleae before and after intracochlear injection of substances that will modify tectorial membrane (TM) mechanics. Because it governs transduction in hair cells, the TM plays a profound role in cochlear amplification; our studies test hypotheses that are based on cochlear models and measurements in isolated TMs and in TM-mutant mice. Aim 3 makes use of SD-OCT's penetrating abilities to test previously untestable fluid-mechanical properties of the organ of Corti. Aim 4 explores the transmission of sound to the cochlea by the middle ear, and how this transmission is modified by feedback from the middle ear muscle, tensor tympani. In preliminary work, tensor tympani modified transmission in a subtle, frequency-dependent manner that could be involved in focusing on particular sound sources, for example during communication. Experiments in which tensor tympani is tensed with voltage pulses will determine how the muscle affects the transmitted sound signal.