Cochlear transducer operating point adaptation

Yuan Zou, Jiefu Zheng, Tianying Ren, Alfred Nuttall

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The operating point (OP) of outer hair cell (OHC) mechanotransduction can be defined as any shift away from the center position on the transduction function. It is a dc offset that can be described by percentage of the maximum transduction current or as an equivalent dc pressure in the ear canal. The change of OP can be determined from the changes of the second and third harmonics of the cochlear microphonic (CM) following a calibration of its initial value. We found that the initial OP was dependent on sound level and cochlear sensitivity. From CM generated by a lower sound level at 74 dB SPL to avoid saturation and suppression of basal turn cochlear amplification, the OHC OP was at constant 57% of the maximum transduction current (an ear canal pressure of -0.1 Pa). To perturb the OP, a constant force was applied to the bony shell of the cochlea at the 18 kHz best frequency location using a blunt probe. The force applied over the scala tympani induced an OP change as if the organ of Corti moved toward the scala vestibuli (SV) direction. During an application of the constant force, the second harmonic of the CM partially recovered toward the initial level, which could be described by two time constants. Removing the force induced recovery of the second harmonic to its normal level described by a single time constant. The force applied over the SV caused an opposite result. These data indicate an active mechanism for OHC transduction OP.

Original languageEnglish (US)
Pages (from-to)2232-2241
Number of pages10
JournalJournal of the Acoustical Society of America
Volume119
Issue number4
DOIs
StatePublished - Apr 2006

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transducers
hair
canals
ear
harmonics
time constant
cochlea
acoustics
organs
recovery
retarding
saturation
Transduction
probes
sensitivity
shift
Cells
Harmonics
Ear
Canals

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

Cite this

Cochlear transducer operating point adaptation. / Zou, Yuan; Zheng, Jiefu; Ren, Tianying; Nuttall, Alfred.

In: Journal of the Acoustical Society of America, Vol. 119, No. 4, 04.2006, p. 2232-2241.

Research output: Contribution to journalArticle

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