Forward and Reverse Travelling Waves in the Cochlea

9320326 山 耳蜗是内耳中的复杂结构，其包含弹性膜，即基底膜，其响应于声音而振荡。 这种振动刺激了被称为毛细胞的机械感觉细胞，毛细胞向听觉神经发送信号。 大约15年前，一项引人注目的发现表明，一组毛细胞，即外毛细胞，本身可以显示运动性，因此可以作为调节耳蜗敏感性的机电元件。 作为该功能的副产品，外毛细胞活动作为声能被传输回耳朵，产生可测量的声音，称为耳声发射，已被科学家和临床医生用作研究耳蜗功能的非侵入性工具。 本计画利用电生理学、电脑模拟及耳声发射的量测，来探讨基底膜振动与外毛细胞活动如何参与正常耳蜗功能的几个新假说。 它将具体评估耳蜗中放大的非线性发生在哪里，以及基底膜是否可能具有不同于经典行波形式的振荡模式。 这种独特的生理学和建模方法的结果将对所有听觉神经科学产生影响，新的发现不仅对听力障碍的处理，而且对听觉通信的设计以及生物力学和生物工程产生重要影响。 ***

9320326 Mountain The cochlea is the complex structure in the inner ear that contains an elastic membrane, the basilar membrane, which oscillates in response to sound. The oscillations stimulate mechanosensory cells called hair cells, which send signals to the auditory nerve. A remarkable finding around 15 years ago showed that one group of hair cells, the outer hair cells, can themselves show motility, and so act as electromechanical elements that can modulate cochlear sensitivity. As a byproduct of that function, the outer hair cell activity is transmitted as acoustical energy back out of the ear, producing measurable sounds called otoacoustic emissions, which have been used by scientists and clinicians as a non-invasive tool to study cochlear function. This project uses electrophysiology, computer simulation, and measurements of the otoacoustic emissions to examine several novel hypotheses about how the basilar membrane vibration and the outer hair cell activity may be involved in normal cochlear function. It will specifically evaluate where the non-linearities in amplification occur in the cochlea, and whether the basilar membrane may have modes of oscillation different from the classical traveling-wave form. Results from this unique combined physiological and modeling approach will have an impact on all auditory neuroscience, and novel findings will have important impact not only on handling of hearing disorders, but on design of auditory communications, and on biomechanics and bioengineering. ***