Transmission matrix analysis of the chinchilla middle ear

Songer, Jocelyn E.; Rosowski, John J.

doi:10.1121/1.2747157

Cited by 24 publications

(41 citation statements)

References 34 publications

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“…Another potential reason for these differences at high frequency is that Ruggero et al ͑2007͒ measured velocity of the lenticular process, and added gains measured across the incudo-stapedial joint, whereas we measured velocity from locations on the footplate and parts of the crura close to the footplate. Mean, SNR > 20 dB (this study) 95% Confidence Interval 10 dB < SNR < 20 dB Décory, 1989;Décory et al, 1990 Chinchilla (this study) Cat (Décory, 1989; Gerbil (Olson, 2001) Guinea Pig (Décory, 1989) Human (Puria et al, 1997) FIG We compared our measured Z C with previous estimates in chinchilla by Ruggero et al ͑1990͒ andRosowski ͑2007a͒. Our Z C is a more direct estimate than either of these previous studies because we derived Z C from simultaneous measurements of P V and V S whereas ͑1͒ Ruggero et al ͑1990͒ combined their own V S measurements ͑see Fig.…”

Section: E Comparison With Other Studies In Chinchillamentioning

confidence: 88%

“…The effect of the hole was smaller as frequency increased, with less than a 3 dB difference by 1 kHz in both the experimental and predicted data. Nonetheless, the detailed shape of the predicted change in ͉P V ͉ is different from the measured change, where much of the differences come from frequency-dependent variations in Z C and Z out that originate in the details of the data used in their calculation ͑Songer and Rosowski, 2007a͒. As for the phase, the ϳ0.15 cycles increase predicted by the model at 150 Hz is consistent with the experimental data around this frequency, but the measured and predicted changes differ slightly at other frequencies.…”

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Middle ear function and cochlear input impedance in chinchilla

Slama

Ravicz

Rosowski

2010

The Journal of the Acoustical Society of America

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Simultaneous measurements of middle ear-conducted sound pressure in the cochlear vestibule P V and stapes velocity V S have been performed in only a few individuals from a few mammalian species. In this paper, simultaneous measurements of P V and V S in six chinchillas are reported, enabling computation of the middle ear pressure gain G ME ͑ratio of P V to the sound pressure in the ear canal P TM ͒, the stapes velocity transfer function SVTF ͑ratio of the product of V S and area of the stapes footplate A FP to P TM ͒, and, for the first time, the cochlear input impedance Z C ͑ratio of P V to the product of V S and A FP ͒ in individuals. ͉G ME ͉ ranged from 25 to 35 dB over 125 Hz-8 kHz; the average group delay between 200 Hz and 10 kHz was about 52 s. SVTF was comparable to that of previous studies. Z C was resistive from the lowest frequencies up to at least 10 kHz, with a magnitude on the order of 10 11 acoustic ohms. P V , V S , and the acoustic power entering the cochlea were good predictors of the shape of the audiogram at frequencies between 125 Hz and 2 kHz.

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Section: E Comparison With Other Studies In Chinchillamentioning

confidence: 88%

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confidence: 99%

Middle ear function and cochlear input impedance in chinchilla

Slama

Ravicz

Rosowski

2010

The Journal of the Acoustical Society of America

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“…*Although middle-ear transmission has not been measured in macaques, studies in other mammals suggest that delays attributable to round-trip middle-ear transmission appear negligible compared with traveling-wave delay (29)(30)(31). † Otoacoustic delays and neural tuning in guinea pigs and chinchillas are generally similar to those in cats (17,20).…”

Section: Auditory-nerve Tuning In Macaques Is Sharper Than In Commonmentioning

confidence: 97%

Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans

Joris

Bergevin

Kalluri

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

120

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Frequency selectivity in the inner ear is fundamental to hearing and is traditionally thought to be similar across mammals. Although direct measurements are not possible in humans, estimates of frequency tuning based on noninvasive recordings of sound evoked from the cochlea (otoacoustic emissions) have suggested substantially sharper tuning in humans but remain controversial. We report measurements of frequency tuning in macaque monkeys, OldWorld primates phylogenetically closer to humans than the laboratory animals often taken as models of human hearing (e.g., cats, guinea pigs, chinchillas). We find that measurements of tuning obtained directly from individual auditory-nerve fibers and indirectly using otoacoustic emissions both indicate that at characteristic frequencies above about 500 Hz, peripheral frequency selectivity in macaques is significantly sharper than in these common laboratory animals, matching that inferred for humans above 4-5 kHz. Compared with the macaque, the human otoacoustic estimates thus appear neither prohibitively sharp nor exceptional. Our results validate the use of otoacoustic emissions for noninvasive measurement of cochlear tuning and corroborate the finding of sharp tuning in humans. The results have important implications for understanding the mechanical and neural coding of sound in the human cochlea, and thus for developing strategies to compensate for the degradation of tuning in the hearing-impaired.auditory filters | comparative hearing S ound waveforms consist of pressure fluctuations in time and space. In the process of transducing mechanical vibrations into neural signals, the cochlea performs a mechanical frequency analysis that decomposes sounds into constituent frequencies (1, 2). The frequency tuning of the cochlear filters plays a critical role in the ability to distinguish and segregate different sounds perceptually. For example, sounds that radiate from different sources superpose in the air, and are thus "mixed up" before striking the eardrums. Based on the output of the cochlear filters, and by comparing responses from the two ears, the nervous system is capable of disentangling the various sounds, grouping related frequency components to identify auditory objects and localize their sources in space (3). The critical role of peripheral frequency selectivity is perhaps best illustrated by the consequences of damage to the inner ear, which typically leads to a degradation of the cochlear filters. The loss of sharp filtering results in an impaired ability to detect signals in noise and to separate different sounds (4). Frequency selectivity is therefore crucial to everyday human communication.The study of the cochlea is hampered by its fragility and inaccessibility. Direct measurements of mechanical or neural frequency tuning in healthy cochleae are only possible in laboratory animals. To date, measurements of the mechanical vibration of the cochlea's basilar membrane have been largely restricted to the basal high-frequency end of the cochlea, where surgical acce...

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“…Initial studies (Songer and Rosowski 2007;Ruggero et al 1990) could not ascertain the highfrequency limit of the transfer function of the chinchilla middle ear because of technical limitations but more recent studies concluded that middle-ear transmission determines the high-frequency cutoff of the audiogram Ravicz et al 2010;Ravicz and Rosowski 2013a, b). The first purpose of the present investigation was to extend our previous measurements of the bandwidth of stapes vibrations in chinchilla ) taking advantage of improved acoustic-stimulus and velocity-recording systems.…”

Section: Introductionmentioning

confidence: 99%

Stapes Vibration in the Chinchilla Middle Ear: Relation to Behavioral and Auditory-Nerve Thresholds

Robles

Temchin²,

Fan³

2015

JARO

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The vibratory responses to tones of the stapes and incus were measured in the middle ears of deeply anesthetized chinchillas using a wide-band acousticstimulus system and a laser velocimeter coupled to a microscope. With the laser beam at an angle of about 40°relative to the axis of stapes piston-like motion, the sensitivity-vs.-frequency curves of vibrations at the head of the stapes and the incus lenticular process were very similar to each other but larger, in the range 15-30 kHz, than the vibrations of the incus just peripheral to the pedicle. With the laser beam aligned with the axis of pistonlike stapes motion, vibrations of the incus just peripheral to its pedicle were very similar to the vibrations of the lenticular process or the stapes head measured at the 40°angle. Thus, the pedicle prevents transmission to the stapes of components of incus vibration not aligned with the axis of stapes piston-like motion. The mean magnitude curve of stapes velocities is fairly flat over a wide frequency range, with a mean value of about 0.19 mm . (s Pa −1 ), has a high-frequency cutoff of 25 kHz (measured at −3 dB re the mean value), and decreases with a slope of about −60 dB/octave at higher frequencies. According to our measurements, the chinchilla middle ear transmits acoustic signals into the cochlea at frequencies exceeding both the bandwidth of responses of auditory-nerve fibers and the upper cutoff of hearing. The phase lags of stapes velocity relative to ear-canal pressure increase approximately linearly, with slopes equivalent to pure delays of about 57-76 μs.

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Transmission matrix analysis of the chinchilla middle ear

Cited by 24 publications

References 34 publications

Middle ear function and cochlear input impedance in chinchilla

Middle ear function and cochlear input impedance in chinchilla

Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans

Stapes Vibration in the Chinchilla Middle Ear: Relation to Behavioral and Auditory-Nerve Thresholds

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