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Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane

Spontaneous otoacoustic emissions (SOAEs) recorded from the ear canal in the absence of sound reflect cochlear amplification, an outer hair cell (OHC) process required for the extraordinary sensitivity and frequency selectivity of mammalian hearing. Although wild-type mice rarely emit, those with mu...

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Autores principales: Cheatham, Mary Ann, Zhou, Yingjie, Goodyear, Richard J., Dallos, Peter, Richardson, Guy P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Society for Neuroscience 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6325554/
https://www.ncbi.nlm.nih.gov/pubmed/30627650
http://dx.doi.org/10.1523/ENEURO.0314-18.2018
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author Cheatham, Mary Ann
Zhou, Yingjie
Goodyear, Richard J.
Dallos, Peter
Richardson, Guy P.
author_facet Cheatham, Mary Ann
Zhou, Yingjie
Goodyear, Richard J.
Dallos, Peter
Richardson, Guy P.
author_sort Cheatham, Mary Ann
collection PubMed
description Spontaneous otoacoustic emissions (SOAEs) recorded from the ear canal in the absence of sound reflect cochlear amplification, an outer hair cell (OHC) process required for the extraordinary sensitivity and frequency selectivity of mammalian hearing. Although wild-type mice rarely emit, those with mutations that influence the tectorial membrane (TM) show an incidence of SOAEs similar to that in humans. In this report, we characterized mice with a missense mutation in Tecta, a gene required for the formation of the striated-sheet matrix within the core of the TM. Mice heterozygous for the Y1870C mutation (Tecta(Y1870C/+)) are prolific emitters, despite a moderate hearing loss. Additionally, Kimura’s membrane, into which the OHC stereocilia insert, separates from the main body of the TM, except at apical cochlear locations. Multimodal SOAEs are also observed in Tecta(Y1870C/+) mice where energy is present at frequencies that are integer multiples of a lower-frequency SOAE (the primary). Second-harmonic SOAEs, at twice the frequency of a lower-frequency primary, are the most frequently observed. These secondary SOAEs are found in spatial regions where stimulus-evoked OAEs are small or in the noise floor. Introduction of high-level suppressors just above the primary SOAE frequency reduce or eliminate both primary and second-harmonic SOAEs. In contrast, second-harmonic SOAEs are not affected by suppressors, either above or below the second-harmonic SOAE frequency, even when they are much larger in amplitude. Hence, second-harmonic SOAEs do not appear to be spatially separated from their primaries, a finding that has implications for cochlear mechanics and the consequences of changes to TM structure.
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spelling pubmed-63255542019-01-09 Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane Cheatham, Mary Ann Zhou, Yingjie Goodyear, Richard J. Dallos, Peter Richardson, Guy P. eNeuro New Research Spontaneous otoacoustic emissions (SOAEs) recorded from the ear canal in the absence of sound reflect cochlear amplification, an outer hair cell (OHC) process required for the extraordinary sensitivity and frequency selectivity of mammalian hearing. Although wild-type mice rarely emit, those with mutations that influence the tectorial membrane (TM) show an incidence of SOAEs similar to that in humans. In this report, we characterized mice with a missense mutation in Tecta, a gene required for the formation of the striated-sheet matrix within the core of the TM. Mice heterozygous for the Y1870C mutation (Tecta(Y1870C/+)) are prolific emitters, despite a moderate hearing loss. Additionally, Kimura’s membrane, into which the OHC stereocilia insert, separates from the main body of the TM, except at apical cochlear locations. Multimodal SOAEs are also observed in Tecta(Y1870C/+) mice where energy is present at frequencies that are integer multiples of a lower-frequency SOAE (the primary). Second-harmonic SOAEs, at twice the frequency of a lower-frequency primary, are the most frequently observed. These secondary SOAEs are found in spatial regions where stimulus-evoked OAEs are small or in the noise floor. Introduction of high-level suppressors just above the primary SOAE frequency reduce or eliminate both primary and second-harmonic SOAEs. In contrast, second-harmonic SOAEs are not affected by suppressors, either above or below the second-harmonic SOAE frequency, even when they are much larger in amplitude. Hence, second-harmonic SOAEs do not appear to be spatially separated from their primaries, a finding that has implications for cochlear mechanics and the consequences of changes to TM structure. Society for Neuroscience 2018-12-26 /pmc/articles/PMC6325554/ /pubmed/30627650 http://dx.doi.org/10.1523/ENEURO.0314-18.2018 Text en Copyright © 2018 Cheatham et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
spellingShingle New Research
Cheatham, Mary Ann
Zhou, Yingjie
Goodyear, Richard J.
Dallos, Peter
Richardson, Guy P.
Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title_full Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title_fullStr Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title_full_unstemmed Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title_short Spontaneous Otoacoustic Emissions in Tecta(Y1870C/+) Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane
title_sort spontaneous otoacoustic emissions in tecta(y1870c/+) mice reflect changes in cochlear amplification and how it is controlled by the tectorial membrane
topic New Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6325554/
https://www.ncbi.nlm.nih.gov/pubmed/30627650
http://dx.doi.org/10.1523/ENEURO.0314-18.2018
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