A physiological frequency-position map of the chinchilla cochlea

Müller, Marcus; Hoidis, Silvi; Smolders, Jean W.T.

doi:10.1016/j.heares.2010.05.021

Cited by 38 publications

(34 citation statements)

References 39 publications

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“…These results suggest that there are sizable contributions to SFOAEs evoked by 1-kHz tones from sources extending somewhere between 6.4 to 7.7 mm (2.5 to 3 oct) basal to the 1-kHz place as we observed significant changes in SFSTCs due to manipulations to the region of the 6-kHz place but not to the region of the 9-kHz place (Figs. 3A and 6A; based on cochlear map from Muller et al 2010). Thus, generation of 1-kHz SFOAEs seems to involve 30 to 40 % of the cochlear length in chinchillas.…”

Section: Figmentioning

confidence: 99%

Tuning of SFOAEs Evoked by Low-Frequency Tones Is Not Compatible with Localized Emission Generation

Charaziak

Siegel

2015

JARO

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Stimulus-frequency otoacoustic emissions (SFOAEs) appear to be well suited for assessing frequency selectivity because, at least on theoretical grounds, they originate over a restricted region of the cochlea near the characteristic place of the evoking tone. In support of this view, we previously found good agreement between SFOAE suppression tuning curves (SF-STCs) and a control measure of frequency selectivity (compound action potential suppression tuning curves (CAP-STC)) for frequencies above 3 kHz in chinchillas. For lower frequencies, however, SF-STCs and were over five times broader than the CAP-STCs and demonstrated more high-pass rather than narrow band-pass filter characteristics. Here, we test the hypothesis that the broad tuning of low-frequency SF-STCs is because emissions originate over a broad region of the cochlea extending basal to the characteristic place of the evoking tone. We removed contributions of the hypothesized basally located SFOAE sources by either pre-suppressing them with a high-frequency interference tone (IT; 4.2, 6.2, or 9.2 kHz at 75 dB sound pressure level (SPL)) or by inducing acoustic trauma at high frequencies (exposures to 8, 5, and lastly 3-kHz tones at 110-115 dB SPL). The 1-kHz SF-STCs and CAP-STCs were measured for baseline, IT present and following the acoustic trauma conditions in anesthetized chinchillas. The IT and acoustic trauma affected SF-STCs in an almost indistinguishable way. The SF-STCs changed progressively from a broad high-pass to narrow band-pass shape as the frequency of the IT was lowered and for subsequent exposures to lowerfrequency tones. Both results were in agreement with the Bbasal sources^hypothesis. In contrast, CAP-STCs were not changed by either manipulation, indicating that neither the IT nor acoustic trauma affected the 1-kHz characteristic place. Thus, unlike CAPs, SFOAEs cannot be considered as a place-specific measure of cochlear function at low frequencies, at least in chinchillas.

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Section: Figmentioning

confidence: 99%

Tuning of SFOAEs Evoked by Low-Frequency Tones Is Not Compatible with Localized Emission Generation

Charaziak

Siegel

2015

JARO

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“…The hole provided a reasonably tight seal around the sensor tip, and the tip was placed approximately at the level of the inner cochlear wall. The location of the ST hole corresponded to a characteristic frequency (CF) of 12 to 18 kHz (Eldridge et al, 1981;M€ uller et al, 2010). Before the end of the experiment, the ossicular chain was interrupted by breaking the narrow shaft between the long process of the incus and the lenticular process.…”

Section: A Preparationmentioning

confidence: 99%

Inner-ear sound pressures near the base of the cochlea in chinchilla: Further investigation

Ravicz

Rosowski

2013

The Journal of the Acoustical Society of America

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The middle-ear pressure gain GMEP, the ratio of sound pressure in the cochlear vestibule PV to sound pressure at the tympanic membrane PTM, is a descriptor of middle-ear sound transfer and the cochlear input for a given stimulus in the ear canal. GMEP and the cochlear partition differential pressure near the cochlear base ΔPCP, which determines the stimulus for cochlear partition motion and has been linked to hearing ability, were computed from simultaneous measurements of PV, PTM, and the sound pressure in scala tympani near the round window PST in chinchilla. GMEP magnitude was approximately 30 dB between 0.1 and 10 kHz and decreased sharply above 20 kHz, which is not consistent with an ideal transformer or a lossless transmission line. The GMEP phase was consistent with a roughly 50-μs delay between PV and PTM. GMEP was little affected by the inner-ear modifications necessary to measure PST. GMEP is a good predictor of ΔPCP at low and moderate frequencies where PV >> PST but overestimates ΔPCP above a few kilohertz where PV ≈ PST. The ratio of PST to PV provides insight into the distribution of sound pressure within the cochlear scalae.

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“…These data need to be appropriately scaled for mice and converted from gain (millimeters per second per Pascal) to displacement (nanometers). The chinchilla-to-mouse conversion is based on the direct comparison between their respective maps as provided by the Müller et al (2005Müller et al ( , 2010. This relation is shown in Figure 5, in which mouse CF is plotted against chinchilla CF, assuming that corresponding CFs are located at equal percentage distances along the basilar membrane.…”

Section: Modeling Of Cochlear Microphonics: Spatial Patterns and CM Cmentioning

confidence: 99%

Using the Cochlear Microphonic as a Tool to Evaluate Cochlear Function in Mouse Models of Hearing

Cheatham

Naik

Dallos

2010

JARO

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The cochlear microphonic (CM) can be a useful analytical tool, but many investigators may not be fully familiar with its unique properties to interpret it accurately in mouse models of hearing. The purpose of this report is to develop a model for generation of the CM in wild-type (WT) and prestin knockout mice. Data and modeling results indicate that in the majority of cases, the CM is a passive response, and in the absence of outer hair cell (OHC) damage, mice lacking amplification are expected to generate WT levels of CM for inputs less than~30 kHz. Hence, this cochlear potential is not a useful metric to estimate changes in amplifier gain. This modeling analysis may explain much of the paradoxical data in the literature. For example, various manipulations, including the application of salicylate and activation of the crossed olivocochlear bundle, reduce the compound action potential but increase or do not change the CM. Based on this current evaluation, CM measurements are consistent with early descriptions where this AC cochlear potential is dominated by basal OHCs, when recorded at the round window.

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A physiological frequency-position map of the chinchilla cochlea

Cited by 38 publications

References 39 publications

Tuning of SFOAEs Evoked by Low-Frequency Tones Is Not Compatible with Localized Emission Generation

Tuning of SFOAEs Evoked by Low-Frequency Tones Is Not Compatible with Localized Emission Generation

Inner-ear sound pressures near the base of the cochlea in chinchilla: Further investigation

Using the Cochlear Microphonic as a Tool to Evaluate Cochlear Function in Mouse Models of Hearing

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