Mechanisms of Mammalian Otoacoustic Emission

Shera, Christopher A.; Guinan, John J.

doi:10.1007/978-0-387-71469-1_9

Cited by 35 publications

(34 citation statements)

References 64 publications

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“…Parameters were chosen to match the measured CF range and tuning of tokay gecko auditory-nerve fibers. The model described here thus serves to test the conjecture that realistic reflection-source OAEs can be produced by nothing more than a slightly irregular array of tuned oscillators ͑Shera, 2003; Shera and Guinan, 2008͒. Despite the simplicity of the assumptions-but consistent with the conjecture-the model produces SFOAEs with characteristics in qualitative and quantitative agreement ͑aside from a significant disparity in overall emission magnitude͒ with those measured in the tokay gecko.…”

Section: Discussionmentioning

confidence: 64%

“…͑14͒ below͔. The derivation sketched below generally parallels analysis of the coherent-reflection model; further discussion and technical details can be found in previous publications ͑e.g., Zweig and Shera, 1995;Talmadge et al, 2000;Shera and Guinan, 2008͒.…”

Section: The Origin Of the Emission Phase Gradientmentioning

confidence: 99%

“…In particular, we develop a simplified model inspired by the lizard inner ear to determine whether the basic principles and predictions of coherent-reflection theory might somehow apply even in the absence of traveling waves. In the process, we test the conjecture ͑Shera, 2003; Shera and Guinan, 2008͒ that the generation of realistic reflection-source OAEs requires nothing more than a slightly irregular array of tuned mechanical resonators.…”

Section: Introductionmentioning

confidence: 99%

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Coherent reflection without traveling waves: On the origin of long-latency otoacoustic emissions in lizards

Bergevin

Shera

2010

The Journal of the Acoustical Society of America

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Lizard ears produce otoacoustic emissions with characteristics often strikingly reminiscent of those measured in mammals. The similarity of their emissions is surprising, given that lizards and mammals manifest major differences in aspects of inner ear morphology and function believed to be relevant to emission generation. For example, lizards such as the gecko evidently lack traveling waves along their basilar membrane. Despite the absence of traveling waves, the phase-gradient delays of gecko stimulus-frequency otoacoustic emissions ͑SFOAEs͒ are comparable to those measured in many mammals. This paper describes a model of emission generation inspired by the gecko inner ear. The model consists of an array of coupled harmonic oscillators whose effective damping manifests a small degree of irregularity. Model delays increase with the assumed sharpness of tuning, reflecting the build-up time associated with mechanical resonance. When tuning bandwidths are chosen to match those of gecko auditory-nerve fibers, the model reproduces the major features of gecko SFOAEs, including their spectral structure and the magnitude and frequency dependence of their phase-gradient delays. The same model with appropriately modified parameters reproduces the features of SFOAEs in alligator lizards. Analysis of the model demonstrates that the basic mechanisms operating in the model are similar to those of the coherent-reflection model developed to describe mammalian emissions. These results support the notion that SFOAE delays provide a noninvasive measure of the sharpness of cochlear tuning.

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Section: Discussionmentioning

confidence: 64%

Section: The Origin Of the Emission Phase Gradientmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coherent reflection without traveling waves: On the origin of long-latency otoacoustic emissions in lizards

Bergevin

Shera

2010

The Journal of the Acoustical Society of America

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“…It has also been recognized by many investigators (e.g., Kemp, 2002;Shera, 2003;Shera and Guinan, 2008) that DPOAE generation is, in fact, a distributed process involving the interaction of numerous wavelets most likely emanating from a region at and basal to f 2 , where the f 1 and f 2 primary-tone traveling-wave (TW) envelopes overlap on the BM. Evidence supporting the distributed nature of DPOAEs is not new (see review in Martin et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Time-domain demonstration of distributed distortion-product otoacoustic emission components

Martin

Stagner

Lonsbury‐Martin

2013

The Journal of the Acoustical Society of America

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Distortion-product otoacoustic emissions (DPOAEs) were measured in rabbits as time waveforms by employing a phase-rotation technique to cancel all components in the final average, except the 2f 1 -f 2 DPOAE. Subsequent filtering allowed the DPOAE waveform to be clearly visualized in the time domain. In most conditions, f 2 was turned off for 6 ms, which produced a gap so that the DPOAE was no longer generated. These procedures allowed the DPOAE onset as well as the decay during the gap to be observed in the time domain. DPOAEs were collected with L 1 ¼ L 2 ¼ 65-dB sound pressure level primary-tone levels for f 2 /f 1 ratios from 1.25 to 1.01 in 0.02 steps. Findings included the appearance of complex onsets and decays for the DPOAE time waveforms as the f 2 /f 1 ratio was decreased and the DPOAE level was reduced. These complexities were unaffected by interference tones (ITs) near the DPOAE frequency place (f dp ), but could be removed by ITs presented above f 2 , which also increased DPOAE levels. Similar outcomes were observed when DPOAEs were measured at a sharp notch in the DPOAE level as a function of the f 2 primary tone frequency, i.e., DP-gram. Both findings were consistent with the hypothesis that the DPOAE-ratio function, and some notches in the DP-gram, are caused by interactions of distributed DPOAE components with unique phases. [http://dx

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“…Preexisting mechanical perturbations which are hypothesised to be the origin of SOAE [24] can be considered as spatial inhomogeneities in the cochlea structure [13]. However there is not yet widespread agreement on the exact mechanisms involved in generating SOAEs.…”

Section: Introductionmentioning

confidence: 99%

Model based prediction of the existence of the spontaneous cochlear microphonic

Ayat¹,

Teal²

2015

AIP Conference Proceedings

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The relation between tympanic membrane higher order modes and standing waves AIP Conference Proceedings 1703, 060008 (2015) Abstract. In the mammalian cochlea, self-sustaining oscillation of the basilar membrane in the cochlea can cause vibration of the ear drum, and produce spontaneous narrow-band air pressure fluctuations in the ear canal. These spontaneous fluctuations are known as spontaneous otoacoustic emissions. Small perturbations in feedback gain of the cochlear amplifier have been proposed to be the generation source of self-sustaining oscillations of the basilar membrane. We hypothesise that the selfsustaining oscillation resulting from small perturbations in feedback gain produce spontaneous potentials in the cochlea. We demonstrate that according to the results of the model, a measurable spontaneous cochlear microphonic must exist in the human cochlea. The existence of this signal has not yet been reported. However, this spontaneous electrical signal could play an important role in auditory research. Successful or unsuccessful recording of this signal will indicate whether previous hypotheses about the generation source of spontaneous otoacoustic emissions are valid or should be amended. In addition according to the proposed model spontaneous cochlear microphonic is basically an electrical analogue of spontaneous otoacoustic emissions. In certain experiments, spontaneous cochlear microphonic may be more easily detected near its generation site with proper electrical instrumentation than is spontaneous otoacoustic emission.

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Mechanisms of Mammalian Otoacoustic Emission

Cited by 35 publications

References 64 publications

Coherent reflection without traveling waves: On the origin of long-latency otoacoustic emissions in lizards

Coherent reflection without traveling waves: On the origin of long-latency otoacoustic emissions in lizards

Time-domain demonstration of distributed distortion-product otoacoustic emission components

Model based prediction of the existence of the spontaneous cochlear microphonic

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