Cochlear micromechanical mechanisms underlying psychoacoustic phenomena

项目摘要/摘要 尽管缺少基本面的音高已经研究了一个多世纪，而且心理物理学 调谐曲线和间隙检测已被用作诊断听力障碍的非侵入性测试， 这些心理声学现象背后的耳蜗力学机制仍不清楚。这个项目 旨在研究导致缺失基本音高的耳蜗微机械机制， 心理物理调谐曲线，以及通过测量根尖网状板(RL)振动来检测间隙 活体沙土鼠耳蜗外毛细胞的末端和听神经电位。我们最重要的是 假设机械缺失的基波是由OHC产生的，并可以在 耳蜗的位置根据刺激频率进行调整。掩蔽物诱导的抑制和增强以及 刺激后RL振动的振荡有助于神经调谐曲线和间隙检测。这 假说将通过进行以下实验来检验。实验一将测量耳蜗- 产生基波的RL振动和听神经电位，并观察噪声的影响 RL和听神经基础上的掩蔽物。不可掩饰的RL和听神经基础将 表明耳蜗会产生基频，而这个耳蜗产生的基频可以是 在调谐到刺激频率的耳蜗处检测到。实验二将测量RL的力学性能 调谐曲线、听神经同步调谐曲线和前向掩蔽调谐曲线以及掩蔽者诱发的 RL探测响应的变化。这项实验的结果将决定是否同时 或前向掩蔽调谐曲线能准确反映RL机械调谐曲线以及是否 掩蔽者引起的RL探测反应的改变有助于耳蜗复合动作电位的形成 (封口)调谐曲线。实验三将测量RL刺激后的振动，并比较 该持续振动持续到间隙检测阈值。这项实验的预期结果将是 提示RL后刺激可兴奋间隙中的内毛细胞和听神经纤维。 这会影响听神经对间隙后刺激的反应。因此，这一结果 研究将揭示缺失基本面的音高背后的耳蜗微机械机制， 心理声学调谐曲线和间隙检测。从这个项目中获得的知识可以使患者受益。 通过优化程序和改善心理声学测试在临床上的解释。

Project Summary/Abstract Although the pitch of missing fundamentals has been studied for more than a century, and psychophysical tuning curves and gap detection have been used as non-invasive tests for diagnosing auditory disorders, the cochlear mechanical mechanisms underlying these psychoacoustic phenomena remain unclear. This project aims to study the cochlear micromechanical mechanisms contributing to the pitch of missing fundamentals, psychophysical tuning curves, and gap detection by measuring the reticular lamina (RL) vibration from apical ends of the outer hair cells (OHCs) and the auditory nerve potential in living gerbil cochleae. Our overarching hypothesis is that the mechanical missing fundamental is generated by OHCs and can be detected at the cochlear locations tuned to stimulus frequencies. Masker-induced suppression and enhancement and poststimulation oscillation of the RL vibration contribute to the neural tuning curves and gap detection. This hypothesis will be tested by conducting the following experiments. Experiment One will measure the cochlea- generated fundamentals in the RL vibration and auditory nerve potential and observe the effect of a noise masker on the RL and auditory nerve fundamentals. The unmaskable RL and auditory nerve fundamentals will indicate that the cochlea can generate the fundamental, and this cochlea-generated fundamental can be detected at cochlear locations tuned to stimulus frequencies. Experiment Two will measure the RL mechanical tuning curves, the auditory nerve simultaneous and forward masking tuning curves, and the masker-induced changes in the RL probe response. The results from this experiment will determine whether the simultaneous or forward masking tuning curve can accurately reflect the RL mechanical tuning curve and whether the masker-induced changes in the RL probe response contribute to the cochlear compound action potential (CAP) tuning curves. Experiment Three will measure the RL poststimulation vibration and compare the duration of this persistent vibration to the gap detection threshold. The expected result from this experiment will indicate that the RL poststimulation can excite the inner hair cells and auditory nerve fibers during the gap period, which affects the auditory nerve response to the stimulus after the gap. Thus, the results from this study will reveal cochlear micromechanical mechanisms underlying the pitch of missing fundamentals, psychoacoustic tuning curves, and gap detection. The knowledge gained from this project can benefit patients by optimizing procedures and improving the interpretation of psychoacoustic tests in clinics.