Using acoustic distortion products to measure the cochlear amplifier gain on the basilar membrane

J. B. Allen, P. F. Fahey

Research output: Contribution to journalArticle

Abstract

Most models of the cochlea developed during the last decade have explained frequency selectivity and sensitivity of the cochlea at threshold by the use of power amplification of the acoustic wave on the basilar membrane. This power amplification has been referred to as the cochlear amplifier (CA). In this paper, a method to measure the cochlear amplifier gain as a function of position along the basilar membrane is derived from a simple model. Next, experimental evidence is presented that strongly restricts the properties of these proposed cochlear amplifier models. Specifically, it is shown that small signals generated by mechanical nonlinearities in the basilar membrane motion are not amplified during basilar membrane propagation, contrary to what would be expected from the cochlear amplifier hypotheses. This paper describes a method of measuring the cochlear power gain as a function of frequency and position, from the stapes to within 2 mm of the place corresponding to the frequency being measured. Experimental results in the cat indicate that the total gain of the cochlear amplifier, over the range of positions measured, must be less than 10 dB. The simplest interpretation of the experimental results is that there is no cochlear amplifier. The results suggest that the cochlea must achieve its frequency selectivity by some other means.

Original languageEnglish (US)
Pages (from-to)178-188
Number of pages11
JournalJournal of the Acoustical Society of America
Volume92
Issue number1
DOIs
StatePublished - Jan 1 1992

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amplifiers
membranes
cochlea
acoustics
products
selectivity
power gain
cats
Acoustics
Membrane
nonlinearity
Cochlea
thresholds
propagation
sensitivity
Amplification

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics

Cite this

Using acoustic distortion products to measure the cochlear amplifier gain on the basilar membrane. / Allen, J. B.; Fahey, P. F.

In: Journal of the Acoustical Society of America, Vol. 92, No. 1, 01.01.1992, p. 178-188.

Research output: Contribution to journalArticle

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