A feedback analysis of outer hair cell dynamics
Name
53834016-MIT.pdf
Description
Full printable version
Size
16.12 MB
Format
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Checksum (MD5)
db12b059b959fbe04a004d831086e5c7
Author(s)
Lu, Timothy K. (Timothy Kuan-Ta), 1981-
Advisor(s)
Rahul Sarpeshkar.
Date Issued
2003
Publisher
Massachusetts Institute of Technology
Abstract
Outer hair cells (OHCs) generate active forces in the mammalian cochlea. Acting as cochlear amplifiers, OHCs can counteract viscous drag, generating high gain at characteristic frequencies and allowing for the sharp frequency selectivity and sensitivity observed in mammals. Excitatory displacement of the basilar membrane causes depolarization of OHC membrane potentials which results in contraction. The motor protein prestin is driven by receptor potentials. However, low-pass filtering by the plasma membrane should severely attenuate the receptor potential at high frequencies (> 100 kHz) where mammalian hearing has been observed. Thus, an open question is how OHCs can respond at these high frequencies despite their low frequency cutoff. Inspired by the use of feedback in mechanical and electrical systems to accelerate slow poles, I demonstrate that negative feedback from the coupling of two mechanical modes of vibration can lead to a membrane time constant speedup and a sharpening of the mechanical response.
Description
Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
Includes bibliographical references (leaves 144-146).
Subjects
Electrical Engineering and Computer Science.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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