Development of otoacoustic emissions in gerbil: Evidence for micromechanical changes underlying development of the place code

Norton, Susan J.; Bargones, Jill Y.; Rubel, Edwin W.

doi:10.1016/0378-5955(91)90008-w

Cited by 83 publications

(36 citation statements)

References 52 publications

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“…Distortion product otoacoustic emissions have proven useful in earlier developmental studies using gerbils from 14 days of age (e.g., Mills and Rubel, 1996;Norton et al, 1991). Speci¢cally, estimates of the cochlear ampli¢er gain with age, as a function of frequency, have been obtained from measurements of the changes in otoacoustic emissions with furosemide intoxication (Mills and Rubel, 1996).…”

Section: Introductionmentioning

confidence: 99%

Development of the base of the cochlea: place code shift in the gerbil

Mills

Rubel

1998

Hearing Research

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Distortion product otoacoustic emission measurements were made at 1/12 octave intervals before and after the injection of furosemide in gerbils aged 15 days after birth to adult, in order to obtain estimates of cochlear amplifier gain as a function of stimulus frequency. The frequency at which the gains went sharply to zero, defined as the`base cutoff frequency', increased from about 20 kHz to over 50 kHz during development. This increase provides further confirmation of the hypothesis that the place code changes during development in the basal part of the cochlea. If the measured base cutoff frequency is identified with the characteristic frequency at the basal end of the cochlea, as defined by electrophysiological measures, then these emission data can be used to generate a frequency-place map as a function of age. The derived place code shift is consistent with published electrophysiological measures, and can be used to extend these measures. Near the base cutoff frequency, the observed cochlear amplifier gain typically dropped sharply from a relative maximum to zero, over a distance of about a half octave. Specifically, this distance appeared to exhibit a curvilinear variation with age, reaching a maximum of 3/4 of an octave at 19^21 days. After transforming from frequency to place using the map derived from emissions, however, the distance between the extreme base and the place associated with the peak gain decreased monotonically from about 1.2 mm at age 15^19 days to 0.6 mm at maturity. This distance is assumed to be characteristic of the length of the active amplification zone for the cochlear amplifier in the base region. Over the same time period, there was approximately a doubling of the rate of amplification with distance from the base, so that the cochlear amplifier gain at the peak actually changed very little from 15 days to adult. z 1998 Published by Elsevier Science B.V. All rights reserved.

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Section: Introductionmentioning

confidence: 99%

Development of the base of the cochlea: place code shift in the gerbil

Mills

Rubel

1998

Hearing Research

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“…The appearance of 2TS roughly coincided with the time when DPOAEs could ¢rst be measured in the gerbil (Norton et al, 1991 ;Mills et al, 1994, Mills andRubel, 1996). Suppression was not expected to be present at 13 dab when driven discharge activity required stimulus levels which were beyond the output limits of the suppressor-tone (105 dB SPL), and the endocochlear potential is severely reduced relative to adults (Woolf et al, 1986 ;McGuirt et al, 1995).…”

Section: Development Of Responses To Two-tone Stimulimentioning

confidence: 66%

“…Emissions could ¢rst be elicited by mid frequency stimuli (Lenoir and Puel, 1987 ;Henley et al, 1989;Norton et al, 1991 ;Mills et al, 1994;Mills and Rubel, 1996), and later for lower frequency tones (Norton et al, 1991 ;Mills et al, 1994). Mills et al (1994) and Mills and Rubel (1996) measured DPOAEs before and after the administration of furosemide in gerbils aged 14 dab to adulthood.…”

Section: Development Of the Cochlear Ampli¢ermentioning

confidence: 99%

“…The development of those cochlear response properties which are likely to be produced primarily by active cochlear processes has been examined extensively using distortion product otoacoustic emissions (DPOAEs) (gerbil: Norton et al, 1991;Mills et al, 1994, Mills andRubel, 1996 ;rat: Henley et al, 1989;Lenoir and Puel, 1987), and less often using 2TS (cat: Fitzakerley et al, 1994a, Fitzakerley et al, 1994b. These studies have shown that the cochlear ampli¢er does, in fact, mature postnatally in altricial animals.…”

Section: Introductionmentioning

confidence: 99%

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Development of single- and two-tone responses of anteroventral cochlear nucleus neurons in gerbil

et al. 1998

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Responses of anteroventral cochlear nucleus (AVCN) neurons in developing gerbils were obtained to single-tone stimuli, and twotone stimuli elicited by best frequency probes presented over a range of intensities. Neurons displayed Type I, Type I/III, and Type III receptive field patterns. Best frequencies ranged from 1.5 to 10.0 kHz. Two-tone suppression (2TS) was first observed in 5 of 16 neurons examined at 14 dab, and in all neurons examined in gerbils aged 15 to 60 dab. Suppression areas grew larger, and discharge rate reductions became greater with age. Features of the two-tone responses that were highly correlated with single-tone responses across age groups include maximum rate reductions and suppression area thresholds. The intensity level of the CF probe-tone also influenced these features of 2TS. Maximum rate reductions to below spontaneous rate levels of activity were common across age groups. Results suggest that the cochlear amplifier is present and fundamentally adult-like by 15 dab for the regions of the cochlea coding the mid frequencies in gerbil. Over the subsequent week, contributions to the developing two-tone responses by the cochlear amplifier increase slightly. Two-tone responses are influenced by central inhibitory mechanisms as early as 14 dab. z 1998 Elsevier Science B.V. All rights reserved.

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“…These studies include aspects of development and ageing of cochlear function (Arjimand et al, 1988;Harris et al, 1990;Norton et al, 1991;Schmiedt et al, 1990;Tarnovski et al, 1991;Woolf and Ryan, 1984) and the occurrence of pathological changes in the cochlear nucleus (Czibulka and Schwartz, 1991;Czibulka and Schwartz, 1993;Faddis and M&inn, 1993;Ostapoff and Mores& 1989). The cochlear nucleus with its complex structural organisation in mammals is the first relay station of the ascending auditory pathway where the afferent fibres from the cochlea terminate.…”

Section: Introductionmentioning

confidence: 99%

The distribution of N-acetylgalactosamine in the cochlear nucleus of the gerbil revealed by lectin binding with soybean agglutinin

Gleich

1994

Hearing Research

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A horseradish peroxidase conjugated lectin from Glycine max (soy bean agglutinin; SBA) was used to characterise the distribution of N-acetylgalactosamine in the cochlear nucleus of the mongolian gerbil. SBA bound differentially to a variety of structures within the cochlear nucleus. Specific SBA labelling was associated with large non-granule neurones of variable size and shape throughout the cochlear nucleus. Compared to adjacent Nissl-stained sections 80% of the non-granule cells in the dorsal cochlear nucleus (DCN) and more than 90% of the non-granule cells in the ventral cochlear nucleus (VCN) bound SBA. The variation in location, size and shape as well as the high percentage of the labelled neurones suggest that cells of several, if not all, non-granule cell types, which have been described for the cochlear nucleus according to the usual Nissl schemes, are SBA positive. Granule cells did not bind SBA because all SBA-labelled cells had diameters above 10 pm. Diffuse labelling, not systematically associated with cells or fibres, was high in the molecular and fusiform cell layers of the DCN and that part of the granule cell area located close to the surface of the VCN. Darkly labelled granules (up to 2 pm diameter) were prominent in the area of the VIIIth nerve root. After long SBA incubations, they were also present in VCN and to a lesser degree in DCN. The results are discussed with respect to findings in other brain areas and the possible co-localisation of gamma aminobutyric acid (GABA), parvalbumin and N-acetylgalactosamine.

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Development of otoacoustic emissions in gerbil: Evidence for micromechanical changes underlying development of the place code

Cited by 83 publications

References 52 publications

Development of the base of the cochlea: place code shift in the gerbil

Development of the base of the cochlea: place code shift in the gerbil

Development of single- and two-tone responses of anteroventral cochlear nucleus neurons in gerbil

The distribution of N-acetylgalactosamine in the cochlear nucleus of the gerbil revealed by lectin binding with soybean agglutinin

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