Modelling the generation of the cochlear microphonic

Ayat, Mohammad; Teal, Paul D.

doi:10.1109/embc.2013.6611211

Cited by 5 publications

(11 citation statements)

References 18 publications

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“…We do not present the details of the model here but refer the reader to [3,5,24] and references within for details on the model and state-space representation of it.…”

Section: -2mentioning

confidence: 99%

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Cochlear microphonic broad tuning curves

Ayat¹,

Teal²,

Searchfield³

et al. 2015

AIP Conference Proceedings

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Abstract. It is known that the cochlear microphonic voltage exhibits much broader tuning than does the basilar membrane motion. The most commonly used explanation for this is that when an electrode is inserted at a particular point inside the scala media, the microphonic potentials of neighbouring hair cells have different phases, leading to cancelation at the electrodes location. In situ recording of functioning outer hair cells (OHCs) for investigating this hypothesis is exceptionally difficult. Therefore, to investigate the discrepancy between the tuning curves of the basilar membrane and those of the cochlear microphonic, and the effect of phase cancellation of adjacent hair cells on the broadness of the cochlear microphonic tuning curves, we use an electromechanical model of the cochlea to devise an experiment. We explore the effect of adjacent hair cells (i.e., longitudinal phase cancellation) on the broadness of the cochlear microphonic tuning curves in different locations. The results of the experiment indicate that active longitudinal coupling (i.e., coupling with active adjacent outer hair cells) only slightly changes the broadness of the CM tuning curves. The results also demonstrate that there is a π phase difference between the potentials produced by the hair bundle and the soma near the place associated with the characteristic frequency based on place-frequency maps (i.e., the best place). We suggest that the transversal phase cancellation (caused by the phase difference between the hair bundle and the soma) plays a far more important role than longitudinal phase cancellation in the broadness of the cochlear microphonic tuning curves. Moreover, by increasing the modelled longitudinal resistance resulting the cochlear microphonic curves exhibiting sharper tuning. The results of the simulations suggest that the passive network of the organ of Corti determines the phase difference between the hair bundle and soma, and hence determines the sharpness of the cochlear microphonic tuning curves.

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“…We do not present the details of the model here but refer the reader to [3,5,24] and references within for details on the model and state-space representation of it.…”

Section: -2mentioning

confidence: 99%

“…i Q =ξ o /T (where T is the piezoelectric transformer ratio.) and i r can be written as a nonlinear antisymmetric saturating function of displacement and velocity of the reticular lamina [3,23,24]. The CM can be obtained as the potential of the endolymphatic space above the basal hair cells.…”

Section: Introductionmentioning

confidence: 99%

Cochlear microphonic broad tuning curves

Ayat¹,

Teal²,

Searchfield³

et al. 2015

AIP Conference Proceedings

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“…where (2) and (3) By applying Newton and Kirchhoff's laws to a relevant section of the model, the model can be represented in state-space form [1,25].…”

Section: Electrical Modelling Of the Organ Of Cortimentioning

confidence: 99%

“…All the physiological activities mentioned here are characterised by using various models. In this paper, we use the model introduced in [1,3,25], but skip the details of the model due to space constraints.…”

Section: Methodsmentioning

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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“…Calculations of this range has typically been based on calculating the longitudinal resistance of each of the scalae from the scala cross-sectional area, and the conductivity of the lymph. These calculations appear in Strelioff (1973), and many models of electrical interactions within the cochlea have used this as a basis (Ayat et al, 2014;Ayat and Teal, 2013;Honrubia et al, 1973;Mistr ık et al, 2009;Ramamoorthy et al, 2007;Teal et al, 2011). Models based on this approach typically include "ladder" networks of resistors.…”

Section: Introductionmentioning

confidence: 99%

Finite element modelling of cochlear electrical coupling

Teal

2016

The Journal of the Acoustical Society of America

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The operation of each hair cell within the cochlea generates a change in electrical potential at the frequency of the vibrating basilar membrane beneath the hair cell. This electrical potential influences the operation of the cochlea at nearby locations and can also be detected as the cochlear microphonic signal. The effect of such potentials has been proposed as a mechanism for the non-local operation of the cochlear amplifier, and the interaction of such potentials has been thought to be the cause of the broadness of cochlea microphonic tuning curves. The spatial extent of influence of these potentials is an important parameter for determining the significance of their effects. Calculations of this extent have typically been based on calculating the longitudinal resistance of each of the scalae from the scala cross sectional area, and the conductivity of the lymph. In this paper, the range of influence of the electrical potential is examined using an electrical finite element model. It is found that the range of influence of the hair cell potential is much shorter than the conventional calculation, but is consistent with recent measurements.

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Modelling the generation of the cochlear microphonic

Cited by 5 publications

References 18 publications

Cochlear microphonic broad tuning curves

Cochlear microphonic broad tuning curves

Model based prediction of the existence of the spontaneous cochlear microphonic

Finite element modelling of cochlear electrical coupling

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