TY - GEN
T1 - A micromechanical model for fast cochlear amplification with slow outer hair cells
AU - Lu, Timothy K.
AU - Zhak, Serhii
AU - Dallos, Peter
AU - Sarpeshkar, Rahul
N1 - Funding Information:
We are grateful for discussions with W. E. Brownell. T.K.L is a HHMI Predoctoral Fellow. This work is also supported in part by a CAREER award from the NSF, a Packard award, and an ONR Young Investigator award.
Publisher Copyright:
Copyright © 2006 by World Scientific Publishing Co. Pte. Ltd.
PY - 2005
Y1 - 2005
N2 - Recent experimental evidence has demonstrated that somatic outer hair cell (OHC) motility is important for amplification in the mammalian cochlea [1,2]. However, under the ‘somatic electromotility’ theory, the transmembrane potential that is responsible for driving the somatic OHC force is subject to low-pass filtering by the electrical RC time constant of the OHC membrane [3]. Numerous mechanisms have been proposed to compensate for the attenuation of the membrane potential by the low membrane time constant at high frequencies [3,4-10]. We present a micromechanical model derived from an engineering-based analysis of cochlear mechanics and experimental data. Our model does not require novel compensatory mechanisms and demonstrates that adequate OHC gain with negative feedback significantly extends closed-loop system bandwidth and increases resonant gain. The OHC gain-bandwidth product, not just bandwidth, determines if high-frequency amplification is possible. Thus, fast cochlear amplification is possible with slow OHCs simply due to in situ feedback dynamics, though our model does not preclude other compensatory mechanisms.
AB - Recent experimental evidence has demonstrated that somatic outer hair cell (OHC) motility is important for amplification in the mammalian cochlea [1,2]. However, under the ‘somatic electromotility’ theory, the transmembrane potential that is responsible for driving the somatic OHC force is subject to low-pass filtering by the electrical RC time constant of the OHC membrane [3]. Numerous mechanisms have been proposed to compensate for the attenuation of the membrane potential by the low membrane time constant at high frequencies [3,4-10]. We present a micromechanical model derived from an engineering-based analysis of cochlear mechanics and experimental data. Our model does not require novel compensatory mechanisms and demonstrates that adequate OHC gain with negative feedback significantly extends closed-loop system bandwidth and increases resonant gain. The OHC gain-bandwidth product, not just bandwidth, determines if high-frequency amplification is possible. Thus, fast cochlear amplification is possible with slow OHCs simply due to in situ feedback dynamics, though our model does not preclude other compensatory mechanisms.
UR - http://www.scopus.com/inward/record.url?scp=33745111670&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33745111670&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:33745111670
T3 - Auditory Mechanisms: Processes and Models - Proceedings of the 9th International Symposium
SP - 433
EP - 441
BT - Auditory Mechanisms
A2 - Nuttall, Alfred L.
A2 - Ren, Tianying
A2 - Gillespie, Peter
A2 - Grosh, Karl
A2 - de Boer, Egbert
PB - World Scientific Publishing Co. Pte Ltd
T2 - 9th International Mechanics of Hearing Workshop on Auditory Mechanisms: Processes and Models, MoH 2005
Y2 - 23 July 2005 through 28 July 2005
ER -