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Tectorial membrane travelling waves underlie abnormal hearing in Tectb mutant mice
Roozbeh Ghaffari1, Alexander J Aranyosi, Guy P Richardson
1Speech and Hearing Bioscience and Technology Program, Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139, USA.
Nature Communications
|October 29, 2010
Summary
The Tectb mutation in mice alters tectorial membrane (TM) waves, reducing hearing sensitivity while sharpening frequency selectivity. This study reveals TM waves
Area of Science:
- Auditory Neuroscience
- Biophysics
- Mechanobiology
Background:
- Mammalian hearing exhibits high sensitivity and frequency selectivity, yet the underlying mechanisms are not fully understood.
- Hearing disorders often decrease sensitivity and broaden frequency tuning, suggesting a link between these auditory properties.
- A mouse model with a Tectb mutation (Tectb(-/-)) presents a unique case of decreased sensitivity coupled with enhanced frequency selectivity.
Purpose of the Study:
- To investigate the impact of the Tectb mutation on the biophysical properties of tectorial membrane (TM) traveling waves.
- To determine how alterations in TM wave propagation contribute to the observed auditory abnormalities in Tectb(-/-) mice.
Main Methods:
- Analysis of tectorial membrane (TM) traveling wave propagation in Tectb(-/-) mice.
- Measurement of spatial extent and propagation velocity of TM waves.
- Correlation of TM wave properties with auditory sensitivity and frequency selectivity.
Main Results:
- The Tectb mutation significantly reduces the spatial extent of TM traveling waves.
- Propagation velocity of TM traveling waves is decreased in Tectb(-/-) mice.
- These TM wave alterations correlate directly with reduced hearing sensitivity and increased frequency selectivity.
Conclusions:
- The Tectb mutation's effects on TM wave propagation fully explain the associated hearing abnormalities.
- Reduced spatial extent of TM waves limits excitation spread, enhancing frequency selectivity.
- Altered TM wave velocity affects hair cell energy coupling, decreasing sensitivity, underscoring the critical role of TM waves in hearing.
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