Speech and Hearing Bioscience and Technology Program, Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139, USA.
Nat Commun. 2010 Oct 19;1(7):96. doi: 10.1038/ncomms1094.
Remarkable sensitivity and exquisite frequency selectivity are hallmarks of mammalian hearing, but their underlying mechanisms remain unclear. Cochlear insults and hearing disorders that decrease sensitivity also tend to broaden tuning, suggesting that these properties are linked. However, a recently developed mouse model of genetically altered hearing (Tectb(-/-)) shows decreased sensitivity and sharper frequency selectivity. In this paper, we show that the Tectb mutation reduces the spatial extent and propagation velocity of tectorial membrane (TM) travelling waves and that these changes in wave propagation are likely to account for all of the hearing abnormalities associated with the mutation. By reducing the spatial extent of TM waves, the Tectb mutation decreases the spread of excitation and thereby increases frequency selectivity. Furthermore, the change in TM wave velocity reduces the number of hair cells that effectively couple energy to the basilar membrane, which reduces sensitivity. These results highlight the importance of TM waves in hearing.
哺乳动物听觉的显著灵敏度和精细的频率选择性是其特征，但它们的潜在机制尚不清楚。耳蜗损伤和听力障碍会降低灵敏度，同时也会使调谐变宽，这表明这些特性是相关的。然而，最近开发的一种遗传改变听觉的小鼠模型（Tectb(-/-)）显示出灵敏度降低和频率选择性更尖锐。在本文中，我们表明 Tectb 突变会降低盖膜（TM）行波的空间范围和传播速度，并且这些波传播的变化可能解释了与突变相关的所有听力异常。通过减小 TM 波的空间范围，Tectb 突变减少了兴奋的传播，从而提高了频率选择性。此外，TM 波速度的变化减少了有效将能量耦合到基底膜的毛细胞数量，从而降低了灵敏度。这些结果强调了 TM 波在听力中的重要性。
