Stereocilin-deficient mice reveal the origin of cochlear waveform distortions.
Stereocilin-deficient mice reveal the origin of cochlear waveform distortions.
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DOI：
10.1038/nature07380
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发表时间：
2008-11-13
期刊：
影响因子：
64.8
通讯作者：
Petit, Christine
中科院分区：
文献类型：
--
作者：
Verpy, Elisabeth;Weil, Dominique;Leibovici, Michel;Goodyear, Richard J.;Hamard, Ghislaine;Houdon, Carine;Lefevre, Gaelle M.;Hardelin, Jean-Pierre;Richardson, Guy P.;Avan, Paul;Petit, Christine
虽然耳蜗是一个放大器和一个非常敏感和微调的声音检测器，但它也会产生明显的机械和电波形失真。这些失真反映了耳蜗内的非线性机械相互作用。通过允许一个音调抑制另一个音调（掩蔽效应），它们有助于语音清晰度。音调也可以联合收割机产生声音，其频率在声学刺激中不存在。这些声音组成耳声发射，广泛用于新生儿听力筛查。由于耳蜗放大和失真都起源于外毛细胞，这是两种感觉感受器细胞之一，因此推测它们源于一种共同的机制。在这里，非线性潜在的耳蜗波形失真依赖于立体声蛋白的存在，一种蛋白质缺陷的隐性形式的人类耳聋。检测到与水平顶部连接器，横向链接，连接相邻的静纤毛外毛细胞的毛束，这些链接是不存在的静纤毛无效突变小鼠。这些老鼠逐渐变聋。然而，在听力开始时，他们的耳蜗灵敏度和频率调谐几乎是正常的，尽管掩蔽大大减少，声学和电波形失真完全没有。从这种独特的功能情况下，我们得出结论，耳蜗波形失真的主要来源是一个偏转依赖的毛束刚度所施加的限制由水平的顶部连接器，而不是从机电换能器通道的固有的非线性行为。
Although the cochlea is an amplifier and a remarkably sensitive and finely tuned detector of sounds, it also produces conspicuous mechanical and electrical waveform distortions. These distortions reflect non-linear mechanical interactions within the cochlea. By allowing one tone to suppress another (masking effect), they contribute to speech intelligibility. Tones can also combine to produce sounds with frequencies not present in the acoustic stimulus. These sounds compose the otoacoustic emissions that are extensively used to screen hearing in newborns. As both cochlear amplification and distortion originate from the outer hair cells, one of the two types of sensory receptor cells, it has been speculated that they stem from a common mechanism. Here, the non-linearity underlying cochlear waveform distortions is shown to rely on the presence of stereocilin, a protein defective in a recessive form of human deafness. Stereocilin was detected in association with horizontal top connectors, lateral links that join adjacent stereocilia within the outer hair cell’s hair bundle, and these links were absent in stereocilin-null mutant mice. These mice become progressively deaf. At the onset of hearing, however, their cochlear sensitivity and frequency tuning were almost normal, although masking was much reduced and both acoustic and electrical waveform distortions were completely lacking. From this unique functional situation, we conclude that the main source of cochlear waveform distortions is a deflection-dependent hair bundle stiffness resulting from constraints imposed by the horizontal top connectors, and not from the intrinsic non-linear behaviour of the mechanoelectrical transducer channel.
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