Organ of Corti Potentials and the Motion of the Basilar Membrane

Fridberger, Anders; Monvel, Jacques Boutet de; Zheng, Jie; Hu, Ning; Zou, Yuan; Ren, Tianying; Nuttall, Alfred L.

doi:10.1523/jneurosci.2711-04.2004

Cited by 82 publications

(114 citation statements)

References 38 publications

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“…I, and measured by Johnston et al (1966). The result is however much closer to the 42 lm space constant reported by Fridberger et al (2004), and the 80 lm space constant reported by Dong and Olson (2013).…”

Section: A Finite Element Modelsupporting

confidence: 84%

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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Section: A Finite Element Modelsupporting

confidence: 84%

Finite element modelling of cochlear electrical coupling

Teal

2016

The Journal of the Acoustical Society of America

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“…The space constant is~80 mm (11,23). In addition, at frequencies above the BF, the STP response becomes dominated by the fast, compression pressure mode, which is not involved in cochlear excitation, at least to first order (24)(25)(26).…”

Section: Resultsmentioning

confidence: 99%

Two-Tone Suppression of Simultaneous Electrical and Mechanical Responses in the Cochlea

Dong

Olson

2016

Biophysical Journal

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Cochlear frequency tuning is based on a mildly tuned traveling-wave response that is enhanced in amplitude and sharpness by outer hair cell (OHC)-based forces. The nonlinear and active character of this enhancement is the fundamental manifestation of cochlear amplification. Recently, mechanical (pressure) and electrical (extracellular OHC-generated voltage) responses were simultaneously measured close to the sensory tissue's basilar membrane. Both pressure and voltage were tuned and showed traveling-wave phase accumulation, evidence that they were locally generated responses. Approximately at the frequency where nonlinearity commenced, the phase of extracellular voltage shifted up, to lead pressure by >1/4 cycle. Based on established and fundamental relationships among voltage, force, pressure, displacement, and power, the observed phase shift was identified as the activation of cochlear amplification. In this study, the operation of the cochlear amplifier was further explored, via changes in pressure and voltage responses upon delivery of a second, suppressor tone. Two different suppression paradigms were used, one with a low-frequency suppressor and a swept-frequency probe, the other with two swept-frequency tones, either of which can be considered as probe or suppressor. In the presence of a high-level low-frequency suppressor, extracellular voltage responses at probe-tone frequencies were greatly reduced, and the pressure responses were reduced nearly to their linear, passive level. On the other hand, the amplifier-activating phase shift between pressure and voltage responses was still present in probe-tone responses. These findings are consistent with low-frequency suppression being caused by the saturation of OHC electrical responses and not by a change in the power-enabling phasing of the underlying mechanics. In the two-tone swept-frequency suppression paradigm, mild suppression was apparent in the pressure responses, while deep notches could develop in the voltage responses. A simple analysis, based on a two-wave differencing scheme, was used to explore the observations.

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“…These results are consistent with the notion that the IHC hairbundle displacement is related to BM velocity at low frequencies (Dallos et al, 1972). The variability and occasional level dependence of the phase lead probably reflect subtly different apposition from experiment to experiment between ciliary bundle and the TM (Freeman and Weiss, 1990;Fridberger et al, 2004). In vivo data obtained with sharp electrodes also reveal significant variability of the IHC phase lead (Cheatham and Dallos, 1999).…”

Section: Input-output Functions Of Ihc Transducer Currentsmentioning

confidence: 98%

Mechanoelectric Transduction of Adult Inner Hair Cells

Song¹,

Dallos

He³

2007

J. Neurosci.

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Inner hair cells (IHCs) are the true sensory receptors in the cochlea; they transmit auditory information to the brain. IHCs respond to basilar membrane (BM) vibration by producing a transducer current through mechanotransducer (MET) channels located at the tip of their stereocilia when these are deflected. The IHC MET current has not been measured from adult animals. We simultaneously recorded IHC transducer currents and BM motion in a gerbil hemicochlea to examine relationships between these two variables and their variation along the cochlear length. Results show that although maximum transducer currents of IHCs are uniform along the cochlea, their operating range is graded and is narrower in the base. The MET current displays adaptation, which along with response magnitude depends on extracellular calcium concentration. The rate of adaptation is invariant along the cochlear length. We introduce a new method of measuring adaptation using sinusoidal stimuli. There is a phase lead of IHC transducer currents relative to sinusoidal BM displacement, reflecting viscoelastic coupling of their cilia and their adaptation process.

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Organ of Corti Potentials and the Motion of the Basilar Membrane

Cited by 82 publications

References 38 publications

Finite element modelling of cochlear electrical coupling

Finite element modelling of cochlear electrical coupling

Two-Tone Suppression of Simultaneous Electrical and Mechanical Responses in the Cochlea

Mechanoelectric Transduction of Adult Inner Hair Cells

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