The response of hair cells in the basal turn of the guinea‐pig cochlea to tones.

Cody, A. R.; Russell, Ian J.

doi:10.1113/jphysiol.1987.sp016428

Cited by 169 publications

(123 citation statements)

References 48 publications

(81 reference statements)

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“…The two distinct parts of the tuning curve (tip and tail) are less evident at lower CFs but become more apparent as CF is increased. Measurements of basilar-membrane tuning have shown similar characteristics to measurements of single-unit FTCs (Cody and Russell, 1987). Both measures revealed sharply tuned tips at CF as well as broadly tuned, low-frequency tails, indicating that neural tuning is a manifestation of mechanical tuning.…”

Section: Introductionmentioning

confidence: 51%

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans

Gruhlke

Birkholz

Neely

et al. 2012

The Journal of the Acoustical Society of America

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Distortion-product otoacoustic emission (DPOAE) suppression tuning curves (STCs) were measured in 65 hearing-impaired (HI) subjects at f 2 frequencies of 2.0, 2.8, 4.0, and 5.6 kHz and L 2 levels relative to sensation level (SL) from 10 dB to as much as 50 dB. Best frequency, cochlearamplifier gain (tip-to-tail difference, T-T), and tuning (Q ERB ) were estimated from STCs. As with normal-hearing (NH) subjects, T-T differences and Q ERB decreased as L 2 increased. T-T differences and Q ERB were reduced in HI ears (compared to normal) for conditions in which L 2 was fixed relative to behavioral threshold (dB SL). When STCs were compared with L 2 at constant sound pressure levels (dB SPL), differences between NH and HI subjects were reduced. The large effect of level and small effect of hearing loss were both confirmed by statistical analyses. Therefore, the magnitude of the differences in DPOAE STCs between NH and HI subjects is mainly dependent on the manner in which level (L 2 ) is specified. Although this conclusion may appear to be at odds with previous, invasive measures of cochlear-response gain and tuning, the apparent inconsistency may be resolved when the manner of specifying stimulus level is taken into account.

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Section: Introductionmentioning

confidence: 51%

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans

Gruhlke

Birkholz

Neely

et al. 2012

The Journal of the Acoustical Society of America

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“…see Hudspeth & Corey, 1977) Ren & Nuttall, 1995). For the purposes of this discussion, however, the exact details of the reverse transduction process are somewhat irrelevant; the most important points are that the outer hair cells are known to operate in a non-linear fashion in vivo (Dallos, 1986;Cody & Russell, 1987), and that they play an important role in cochlear amplification. The outer hair cells hence present themselves as an obvious source of the distortion observed in this report.…”

Section: Discussionmentioning

confidence: 99%

“…In most non-linear systems, even-order distortion (such as that at 2FÑ) is accompanied by large DC shifts. But DC shifts in the basal turns of the cochlea are known to be extremely small, both on the basilar membrane (LePage, 1987;Cooper & Rhode, 1992) and in the receptor potentials of the outer hair cells (Cody & Russell, 1987). In the model of Fig.…”

Section: Odd-vs Even-order Distortionmentioning

confidence: 99%

Harmonic distortion on the basilar membrane in the basal turn of the guinea‐pig cochlea

Cooper

1998

The Journal of Physiology

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Mechanical responses to pure‐tone stimuli were recorded from the basilar membrane in the basal turn of the guinea‐pig cochlea using a displacement‐sensitive laser interferometer. The harmonic content of the responses was evaluated using Fourier analysis. Harmonic distortion products were observed in many of the basilar membrane responses. Response components locked to twice the frequency of the stimulus (i.e. 2F0) were the largest of the distortion products. The second harmonic responses showed a bimodal frequency distribution at low to moderate sound pressure levels: one peak occurred around the preparation's best or most sensitive frequency (i.e. when F0≈ 17 kHz), and another occurred around one‐half of the best frequency (when F0≈ 8.5 kHz). The absolute levels of most distortion products increased progressively with increasing stimulus strength. When expressed with respect to the levels of the fundamental responses, however, the distortion levels usually decreased with increasing stimulus strength. The levels of the distortion decreased (in both absolute and relative terms) with deterioration in the physiological condition of the cochlea. Maximum second harmonic distortion levels amounted to ≈3.5 and ≈28 % of the fundamental responses to tones near and below the best frequency, respectively. The above findings are shown to be consistent with a highly simplified model of cochlear mechanics which incorporates an asymmetric, saturating non‐linearity in a positive feedback loop.

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“…The rate of presentation was 10 bursts per s. Cochlear responses were amplified (gain, 2,000) by a differential amplifier (Grass P511K), averaged (256 samples), and saved on a Pentium PC computer (100 Mhz; Dell Dimension). The stored potentials could then be digitally filtered with a low-pass setting at 2.5 kHz to measure the compound action potential (CAP) of the auditory nerve, and the summating potential (SP) reflecting the summed intracellular dc receptor potential, mainly generated by the inner hair cells (IHCs) (1). Filtering cochlear potentials with a band-pass filter centered on the frequency of tone burst stimulation allows extraction of the cochlear microphonic (CM) reflecting the summed intracellular ac receptor potential mainly generated by outer hair cells (OHCs) (17).…”

Section: Targeting Construction and Generation Of Otosmentioning

confidence: 99%

Deafness and Cochlear Fibrocyte Alterations in Mice Deficient for the Inner Ear Protein Otospiralin

Delprat

Ruel

Guitton

et al. 2005

Molecular and Cellular Biology

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In the cochlea, the mammalian auditory organ, fibrocytes of the mesenchymal nonsensory regions play important roles in cochlear physiology, including the maintenance of ionic and hydric components in the endolymph. Occurrence of human deafness in fibrocyte alterations underlines their critical roles in auditory function. We recently described a novel gene, Otos, which encodes otospiralin, a small protein of unknown function that is produced by the fibrocytes of the cochlea and vestibule. We now have generated mice with deletion of Otos and found that they show moderate deafness, with no frequency predominance. Histopathology revealed a degeneration of type II and IV fibrocytes, while hair cells and stria vascularis appeared normal. Together, these findings suggest that impairment of fibrocytes caused by the loss in otospiralin leads to abnormal cochlear physiology and auditory function. This moderate dysfunction may predispose to age-related hearing loss.Within the cochlea, the mammalian auditory organ, mesenchymal nonsensory regions (i.e., the spiral limbus proximal to the cochlear axis and the spiral ligament forming the lateral wall of the cochlea) contain fibrocytes that play important roles in cochlear physiology. In the spiral ligament, these fibrocytes form distinct groups according to their location, morphological appearance, and marker expression, which suggest their functional specialization (26). Thus, the circumferentially oriented type III fibrocytes lining the otic capsule and the spindleshaped type IV fibrocytes lateral to the basilar membrane package the cochlear content and buffer mechanical constraints generated by sound vibrations (8). The type I fibrocytes (behind the stria vascularis), tightly packed with collagen bundles, shape the curvature of the lateral wall. Type II fibrocytes (below the stria vascularis) and type V fibrocytes (above the stria vascularis) are rich in mitochondria and form many interdigitating processes, indicating high metabolic and exchange activities. Type I, II, and V fibrocytes and basal and intermediate cells of the stria vascularis are all interconnected with gap junctions (10). This gap-junctioned network is postulated to be involved in ion and water circulation, including potassium recycling (34). Potassium is indeed central to the cochlear physiology, since it is the charge-carrying ion for the sensory transduction. It is secreted by the marginal cells of the stria vascularis to maintain a very high concentration (150 mM) in the endolymph, the extracellular fluid bathing hair cell stereocilia. Recycling of potassium though the fibrocyte network is one of several processes that provide potassium to intermediate cells of the stria vascularis (28, 34). This permanent flux of potassium cycling in the cochlea generates the so-called "endocochlear potential " (ϩ85 mV), which gives the main driving force for potassium entry into the sensory hair cell.Progress in the functional characterization of the cochlear fibrocytes has been made with the discovery of proteins exp...

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The response of hair cells in the basal turn of the guinea‐pig cochlea to tones.

Cited by 169 publications

References 48 publications

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans

Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans

Harmonic distortion on the basilar membrane in the basal turn of the guinea‐pig cochlea

Deafness and Cochlear Fibrocyte Alterations in Mice Deficient for the Inner Ear Protein Otospiralin

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