Outer hair cell somatic electromotility in vivo and power transfer to the organ of corti

Sripriya Ramamoorthy, Alfred Nuttall

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The active amplification of sound-induced vibrations in the cochlea, known to be crucial for auditory sensitivity and frequency selectivity, is not well understood. The outer hair cell (OHC) somatic electromotility is a potential mechanism for such amplification. Its effectiveness in vivo is putatively limited by the electrical low-pass filtering of the cell's transmembrane potential. However, the transmembrane potential is an incomplete metric. We propose and estimate two metrics to evaluate the effectiveness of OHC electromotility in vivo. One metric is the OHC electromechanical ratio defined as the amplitude of the ratio of OHC displacement to the change in its transmembrane potential. The in vivo electromechanical ratio is derived from the recently measured in vivo displacements of the reticular lamina and the basilar membrane at the 19 kHz characteristic place in guinea pigs and using a model. The ratio, after accounting for the differences in OHC vibration in situ due to the impedances from the adjacent structures, is in agreement with the literature values of the in vitro electromechanical ratio measured by others. The second and more insightful metric is the OHC somatic power. Our analysis demonstrates that the organ of Corti is nearly optimized to receive maximum somatic power in vivo and that the estimated somatic power could account for the active amplification.

Original languageEnglish (US)
Pages (from-to)388-398
Number of pages11
JournalBiophysical Journal
Volume102
Issue number3
DOIs
StatePublished - Feb 8 2012

Fingerprint

Outer Auditory Hair Cells
Organ of Corti
Membrane Potentials
Vibration
Basilar Membrane
Cochlea
Electric Impedance
Guinea Pigs

ASJC Scopus subject areas

  • Biophysics

Cite this

Outer hair cell somatic electromotility in vivo and power transfer to the organ of corti. / Ramamoorthy, Sripriya; Nuttall, Alfred.

In: Biophysical Journal, Vol. 102, No. 3, 08.02.2012, p. 388-398.

Research output: Contribution to journalArticle

@article{6af7f73b380a4c1390313668a398d8be,
title = "Outer hair cell somatic electromotility in vivo and power transfer to the organ of corti",
abstract = "The active amplification of sound-induced vibrations in the cochlea, known to be crucial for auditory sensitivity and frequency selectivity, is not well understood. The outer hair cell (OHC) somatic electromotility is a potential mechanism for such amplification. Its effectiveness in vivo is putatively limited by the electrical low-pass filtering of the cell's transmembrane potential. However, the transmembrane potential is an incomplete metric. We propose and estimate two metrics to evaluate the effectiveness of OHC electromotility in vivo. One metric is the OHC electromechanical ratio defined as the amplitude of the ratio of OHC displacement to the change in its transmembrane potential. The in vivo electromechanical ratio is derived from the recently measured in vivo displacements of the reticular lamina and the basilar membrane at the 19 kHz characteristic place in guinea pigs and using a model. The ratio, after accounting for the differences in OHC vibration in situ due to the impedances from the adjacent structures, is in agreement with the literature values of the in vitro electromechanical ratio measured by others. The second and more insightful metric is the OHC somatic power. Our analysis demonstrates that the organ of Corti is nearly optimized to receive maximum somatic power in vivo and that the estimated somatic power could account for the active amplification.",
author = "Sripriya Ramamoorthy and Alfred Nuttall",
year = "2012",
month = "2",
day = "8",
doi = "10.1016/j.bpj.2011.12.040",
language = "English (US)",
volume = "102",
pages = "388--398",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "3",

}

TY - JOUR

T1 - Outer hair cell somatic electromotility in vivo and power transfer to the organ of corti

AU - Ramamoorthy, Sripriya

AU - Nuttall, Alfred

PY - 2012/2/8

Y1 - 2012/2/8

N2 - The active amplification of sound-induced vibrations in the cochlea, known to be crucial for auditory sensitivity and frequency selectivity, is not well understood. The outer hair cell (OHC) somatic electromotility is a potential mechanism for such amplification. Its effectiveness in vivo is putatively limited by the electrical low-pass filtering of the cell's transmembrane potential. However, the transmembrane potential is an incomplete metric. We propose and estimate two metrics to evaluate the effectiveness of OHC electromotility in vivo. One metric is the OHC electromechanical ratio defined as the amplitude of the ratio of OHC displacement to the change in its transmembrane potential. The in vivo electromechanical ratio is derived from the recently measured in vivo displacements of the reticular lamina and the basilar membrane at the 19 kHz characteristic place in guinea pigs and using a model. The ratio, after accounting for the differences in OHC vibration in situ due to the impedances from the adjacent structures, is in agreement with the literature values of the in vitro electromechanical ratio measured by others. The second and more insightful metric is the OHC somatic power. Our analysis demonstrates that the organ of Corti is nearly optimized to receive maximum somatic power in vivo and that the estimated somatic power could account for the active amplification.

AB - The active amplification of sound-induced vibrations in the cochlea, known to be crucial for auditory sensitivity and frequency selectivity, is not well understood. The outer hair cell (OHC) somatic electromotility is a potential mechanism for such amplification. Its effectiveness in vivo is putatively limited by the electrical low-pass filtering of the cell's transmembrane potential. However, the transmembrane potential is an incomplete metric. We propose and estimate two metrics to evaluate the effectiveness of OHC electromotility in vivo. One metric is the OHC electromechanical ratio defined as the amplitude of the ratio of OHC displacement to the change in its transmembrane potential. The in vivo electromechanical ratio is derived from the recently measured in vivo displacements of the reticular lamina and the basilar membrane at the 19 kHz characteristic place in guinea pigs and using a model. The ratio, after accounting for the differences in OHC vibration in situ due to the impedances from the adjacent structures, is in agreement with the literature values of the in vitro electromechanical ratio measured by others. The second and more insightful metric is the OHC somatic power. Our analysis demonstrates that the organ of Corti is nearly optimized to receive maximum somatic power in vivo and that the estimated somatic power could account for the active amplification.

UR - http://www.scopus.com/inward/record.url?scp=84856738593&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84856738593&partnerID=8YFLogxK

U2 - 10.1016/j.bpj.2011.12.040

DO - 10.1016/j.bpj.2011.12.040

M3 - Article

C2 - 22325260

AN - SCOPUS:84856738593

VL - 102

SP - 388

EP - 398

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 3

ER -