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Research Article

Collagen-Based Mechanical Anisotropy of the Tectorial Membrane: Implications for Inter-Row Coupling of Outer Hair Cell Bundles

  • Núria Gavara,

    Affiliation: Auditory Mechanics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States of America

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  • Richard S. Chadwick mail

    chadwick@helix.nih.gov

    Affiliation: Auditory Mechanics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States of America

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  • Published: March 18, 2009
  • DOI: 10.1371/journal.pone.0004877

Reader Comments (1)

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The stiffness of the TM

Posted by irousso on 19 Mar 2009 at 20:18 GMT

I would like to draw the attention to the results reported by Ghaffari et al. PNAS 104:16510-16515 (2007) (reference 18 in this manuscript). In this report the stiffness of the TM was shown to be ~141 and 51 kPA for basal and apical TM segments, which is simillar to the stiffness we have detected (Gueta et al. PNAS 103:4790–14795, 2006) (reference 13 in this manuscript).

I therefore assert that the statement: "Gueta et al. reported graded stiffness along the cochlea, but the observed magnitudes were at least an order of magnitude greater than all published data" is inaccurate.


RE: The stiffness of the TM

chadwick replied to irousso on 20 Mar 2009 at 15:43 GMT

Ghaffari et al. report values of 47+ -12 KPa and 17+ - 5 KPa for base and apical segments of TM. These values were inferred from an isotropic wave speed model and not direct measurements. Ghaffari et al. also state that Gueta et al. reported significantly higher values at the base than all other measurements. We don't understand where irousso obtained the values from Ghaffari et al., but nevertheless irousso has a point that the apical value from Gueta et al is similar to Ghaffari et al.

No competing interests declared.

RE: RE: The stiffness of the TM

irousso replied to chadwick on 22 Mar 2009 at 08:22 GMT

I think it is important (again) to be accurate when providing information. Note that Ghaffari et al. reported shear moduli which can be roughly estimated to be 1/3 of Young’s moduli, which we reported.

In addition, I fail to understand the distinction between model based vs. direct measurements. To the best of my knowledge all published values are model based

No competing interests declared.