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Does the human cochlea work like a laser?

Does the human cochlea work like a laser?
Does the human cochlea work like a laser?
The sharply tuned sense of hearing in humans is believed to be due to active amplification in the cochlea. One seemingly natural consequence of this ‘cochlear amplifier’ is the existence of spontaneous otoacoustic emissions (SOAEs), narrow-band tones that are detected in the ear canals of 33% to 70% of all normal-hearing individuals (1). The mechanisms underlying the features and generation of SOAEs have long been a subject of debate. Zweig and Shera (2) argue that SOAEs are created by multiple travelling-wave reflections between the middle ear boundary and a dense array of inhomogeneities scattered throughout the cochlea; Shera (3) likens this process to activity in a laser cavity. This theory is contrary to previous ideas which assume independently unstable oscillators in the cochlea. This work uses a state space formulation of the cochlea to test the predictions made by Zweig and Shera (2). The Elliott et al. model of the cat cochlea (4) has been revised to describe characteristics of the human cochlea. Linear instabilities arise across a wide bandwidth of frequencies when the smooth spatial variation of basilar membrane impedance is disturbed. The salient features of Zweig and Shera’s theory (2) are observed in this active model given perturbations in the distribution of feedback gain along the cochlea. A step change in gain is used to demonstrate system instability.
Ku, E.M.
62767aa7-93fd-4325-a64d-96cb2c3e4ce9
Elliott, S.J.
721dc55c-8c3e-4895-b9c4-82f62abd3567
Lineton, B.
1ace4e96-34da-4fc4-bc17-a1d82b2ba0e2
Ku, E.M.
62767aa7-93fd-4325-a64d-96cb2c3e4ce9
Elliott, S.J.
721dc55c-8c3e-4895-b9c4-82f62abd3567
Lineton, B.
1ace4e96-34da-4fc4-bc17-a1d82b2ba0e2

Ku, E.M., Elliott, S.J. and Lineton, B. (2008) Does the human cochlea work like a laser? FESM Postgraduate Research Showcase, Southampton, UK. 19 Mar 2008.

Record type: Conference or Workshop Item (Poster)

Abstract

The sharply tuned sense of hearing in humans is believed to be due to active amplification in the cochlea. One seemingly natural consequence of this ‘cochlear amplifier’ is the existence of spontaneous otoacoustic emissions (SOAEs), narrow-band tones that are detected in the ear canals of 33% to 70% of all normal-hearing individuals (1). The mechanisms underlying the features and generation of SOAEs have long been a subject of debate. Zweig and Shera (2) argue that SOAEs are created by multiple travelling-wave reflections between the middle ear boundary and a dense array of inhomogeneities scattered throughout the cochlea; Shera (3) likens this process to activity in a laser cavity. This theory is contrary to previous ideas which assume independently unstable oscillators in the cochlea. This work uses a state space formulation of the cochlea to test the predictions made by Zweig and Shera (2). The Elliott et al. model of the cat cochlea (4) has been revised to describe characteristics of the human cochlea. Linear instabilities arise across a wide bandwidth of frequencies when the smooth spatial variation of basilar membrane impedance is disturbed. The salient features of Zweig and Shera’s theory (2) are observed in this active model given perturbations in the distribution of feedback gain along the cochlea. A step change in gain is used to demonstrate system instability.

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Published date: 2008
Venue - Dates: FESM Postgraduate Research Showcase, Southampton, UK, 2008-03-19 - 2008-03-19

Identifiers

Local EPrints ID: 65261
URI: http://eprints.soton.ac.uk/id/eprint/65261
PURE UUID: d7568e70-103c-4bd7-a7e7-005f5b1beeac
ORCID for B. Lineton: ORCID iD orcid.org/0000-0003-4784-7762

Catalogue record

Date deposited: 09 Mar 2009
Last modified: 16 Mar 2024 03:31

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Contributors

Author: E.M. Ku
Author: S.J. Elliott
Author: B. Lineton ORCID iD

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