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The hair-cell bundle as a sensory antenna and mechanical amplifier for hearing| old_uid | 9608 |
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| title | The hair-cell bundle as a sensory antenna and mechanical amplifier for hearing |
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| start_date | 2011/02/03 |
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| schedule | 12h |
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| online | no |
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| summary | The remarkable technical specifications of vertebrate hearing emerge from mechanical amplification of sound-evoked vibrations by sensory hair cells. I will show that hair cell’s mechano-receptive antenna, the hair bundle, can also function as a force generator and even oscillate spontaneously. Spontaneous oscillations are thought to arise from the interplay between negative hair-bundle stiffness, the activity of adaptation motors and Ca2+ feedback on the force that the motors can produce. An oscillatory hair bundle functions as a frequency-selective, nonlinear amplifier that qualitatively recapitulates the key features of the auditory amplifier. Thermal fluctuations jostle the response of a single hair bundle to weak stimuli and seriously limit amplification in vitro. I will show that elastic coupling of a hair bundle to neighbors effectively reduces noise and enhances amplification to a level that can accord with in vivo measurements. I will argue that auditory detection by “critical” oscillators provides a useful framework to apprehend the dazzling performances of mammalian hearing. |
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| responsibles | Baran |
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