Corti Fluid Is a Medium for Outer Hair Cell Force Transmission.
Mohammad Shokrian1, Wei-Ching Lin1, Anes Macić1
1Departments of Mechanical Engineering, University of Rochester, Rochester, New York 14627.
Summary
Active outer hair cells (OHCs) use fluid dynamics in the cochlea to selectively amplify sounds. This mechanism explains how the ear achieves precise frequency tuning despite non-selective OHC amplification.
Area of Science:
- Auditory Neuroscience
- Bioacoustics
- Mechanobiology
Background:
- Mammalian cochlear sound amplification enhances frequency resolution.
- Vibrations near outer hair cells (OHCs) are amplified non-selectively, with the underlying mechanism unclear.
Purpose of the Study:
- To investigate how the cochlea achieves selective sound amplification.
- To elucidate the role of active force transmission through the organ of Corti's extracellular fluid.
Main Methods:
- Computational modeling of cochlear mechanics.
- Experiments using excised gerbil cochleae.
- Analysis of outer hair cell (OHC) motility and its effect on fluid dynamics.
Main Results:
- Active force transmission via Corti fluid explains selective amplification.
- Corti fluid dynamics critically influence OHC-Deiters cell joint motion.
- Distinct frequency tuning patterns observed in basilar membrane, ODJ region, and reticular lamina.
Conclusions:
- Active OHCs utilize the organ of Corti's structure and fluid for frequency selectivity.
- Cochlear fluid dynamics enable amplification and suppression of vibrations, mimicking neural tuning.
- This mechanism enhances frequency resolution crucial for hearing.
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