Effect of the Attachment of the Tectorial Membrane on Cochlear Micromechanics and Two-Tone Suppression

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• 作者：Julien Meaud^&dagger ; ; ^{julien.meaud@me.gatech.edu" class="auth_mail} ; Karl Grosh^&dagger ; ; ^&Dagger ;
• 刊名：Biophysical Journal
• 出版年：18 March, 2014
• 年：2014
• 卷：106
• 期：6
• 页码：1398-1405
• 全文大小：1448 K

文摘

The mechanical stimulation of the outer hair cell hair bundle (HB) is a key step in nonlinear cochlear amplification. We show how two-tone suppression (TTS), a hallmark of cochlear nonlinearity, can be used as an indirect measure of HB stimulation. Using two different nonlinear computational models of the cochlea, we investigate the effect of altering the mechanical load applied by the tectorial membrane (TM) on the outer hair cell HB. In the first model (TM-A model), the TM is attached to the spiral limbus (as in wild-type animals); in the second model (TM-D model), the TM is detached from the spiral limbus (mimicking the cochlea of Otoa^EGFP/EGFP mutant mice). As in recent experiments, model simulations demonstrate that the absence of the聽TM attachment does not preclude cochlear amplification. However, detaching the TM alters the mechanical load applied by the TM on the HB at low frequencies and therefore affects TTS by low-frequency suppressors. For low-frequency suppressors, the suppression threshold obtained with the TM-A model corresponds to a constant suppressor displacement on the basilar membrane (as in experiments with wild-type animals), whereas it corresponds to a constant suppressor velocity with the TM-D model. The predictions with the TM-D model could be tested by measuring TTS on the basilar membrane of the Otoa^EGFP/EGFP mice to improve our understanding of the fundamental workings of the cochlea.