Olivocochlear Efferent Systems and Cochlear Physiology

橄榄耳蜗传出系统和耳蜗生理学

• 批准号: 7162938
• 负责人: JOHN J GUINAN
• 金额: $ 22.05万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-06-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7162938
• 关键词: Accounting; Acoustic Nerve; Acoustic Trauma; Affect; Amplifiers; Animals; Area; Basilar Membrane; Cavia; Cell membrane; Characteristics; Cochlea; Code; Couples; Data; Development; Devices; Efferent Neurons; Electric Capacitance; Electric Stimulation; Feedback; Felis catus; Fire - disasters; Frequencies; Goals; Hair Cells; Hearing; In Situ; In Vitro; Learning; Measurement; Measures; Mechanics; Medial; Motion; Nerve Fibers; Outer Hair Cells; Pathology; Pattern; Phase; Physiological; Physiology; Play; Property; Publishing; Pump; Role; Stimulus; Structure; System; Tail; Testing; Time; Travel; Work; base; cell motility; in vivo; insight; relating to nervous system; response; sound; theories; tool

DESCRIPTION (provided by applicant): Our goal is to understand how outer hair cells (OHCs) produce the high sensitivity of mammalian hearing. Great progress has been made in understanding the properties of isolated OHCs, but there are fundamental unanswered questions about how OHCs work in intact cochleas. Medial olivocochlear (MOC) efferent neurons innervate OHCs and provide an important tool for understanding OHC-based mechanisms. To study the mechanical effects of OHCs in vivo, we will measure basilar-membrane (BM) motion and auditory-nerve (AN) firing patterns and the changes produced in these responses by electrical stimulation of MOC efferents. Our recent work provides strong evidence for the existence of a second traveling wave along the cochlea, a wave that may couple OHC motility to BM motion. The proposed work will characterize the properties of this second wave and its relationship to the classic transverse traveling wave. This wil be done (1) at frequencies well below the local characteristic frequency (CF), where stiffness dominates the mechanical response and the effects of the two traveling waves can be studied without the complications produced by cochlear amplification, and (2) at frequencies near CF where the cochlear amplifier has its primary effects. Our work, and that of others, has shown that the "slow effect" of MOC stimulation is due to a decrease in OHC stiffness. This stiffness change will be exploited to determine how OHC stiffness affects cochlear properties such as CF, and to test the OHC piezoelectric theory, a theory that may account for how OHC somatic motility can be effective at frequencies above the OHC membrane cut-off frequency. The results of the proposed work will help to flesh out a new picture of cochlear mechanics. Mechanics is a key area of cochlear function that is disrupted by many of the pathologies that affect hearing. Understanding cochlear mechanics, and the role of OHCs in cochlear mechanics, is essential for progress in almost all aspects of hearing.

描述(申请人提供)：我们的目标是了解外毛细胞是如何产生哺乳动物听力的高灵敏度的。在了解孤立的内耳毛细胞的特性方面已经取得了很大的进展，但关于内耳毛细胞如何在完整的耳蜗中工作的基本问题仍未得到解答。内侧橄榄耳蜗区(MOC)传出神经元支配着OHC，为了解OHC的机制提供了重要的工具。为了研究内耳毛细胞在体内的力学效应，我们将测量基底膜(BM)运动和听神经(AN)放电模式以及电刺激MOC传出时这些反应的变化。 我们最近的工作提供了强有力的证据，证明了沿耳蜗处存在第二个行波，这个波可能会将OHC运动与BM运动耦合在一起。这项工作将描述这种第二波的性质，以及它与经典横向行波的关系。这将在(1)远低于局部特征频率(Cf)的频率下进行，在该频率处，机械响应由僵硬主导，并且可以研究两个行波的影响，而不会产生耳蜗声放大所产生的并发症；(2)在接近Cf的频率处，其中耳蜗放放具有其主要效应。我们和其他人的工作表明，刺激MOC的“慢效应”是由于OHC刚性的减少。这种僵硬变化将被用来确定OHC僵硬如何影响耳蜗特性，如CF，并测试OHC压电学理论，该理论可能解释OHC躯体运动如何在高于OHC膜截止频率的频率下有效。这项拟议工作的结果将有助于充实耳蜗力学的新图景。力学是耳蜗功能的一个关键领域，许多影响听力的病理因素都会破坏这一领域。了解耳蜗力学，以及内耳毛细胞在耳蜗力学中的作用，对于听力几乎所有方面的进步都是至关重要的。