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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2-3
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pubmed:dateCreated |
1990-4-13
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pubmed:abstractText |
Distortion-product emissions at 2f1-f2 were measured in developing, pigmented rats to determine the characteristics of the functional onset and maturation of these emitted responses. Distortion-product testing was conducted on postnatal days 12, 14, 18, 21, 24, 28, and 51. The geometric-mean frequencies of the primaries were tested at one-half octave intervals, between 4 and 11.3 kHz. No emissions were detected on postnatal day 12; however, by day 14, emissions were measured at geometric-mean frequencies between 5.7 and 11.3 kHz, but not at 4 kHz. By the 18th postnatal day, all animals had measurable emissions at 4, 5, 7, 8, and 11.3 kHz. Both the functional onset and maturation of high- to midfrequency emissions developed before those elicited by lower-frequency primaries. Response/growth or input/output functions for the higher frequencies exhibited 'adult-like' properties that included an increase in maximum amplitude and 'saturation' at high levels of stimulation by the third to fourth postnatal week. Maturation of the lower-frequency responses progressed at a slower rate. These results differ somewhat from those reported previously for the neonatal albino rat. However, the present findings were based upon a wider frequency range of primary tones, lower levels of acoustic stimulation, and a measuring system with a significantly lower noise floor. These results are consistent with documented periods of the anatomical maturation of the rat outer hair-cell system and establish a functional 'baseline' for future studies utilizing agents that damage the developing cochlea.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
|
pubmed:issn |
0378-5955
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pubmed:author | |
pubmed:issnType |
Print
|
pubmed:volume |
43
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
141-8
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:2312410-Acoustic Stimulation,
pubmed-meshheading:2312410-Acoustics,
pubmed-meshheading:2312410-Animals,
pubmed-meshheading:2312410-Animals, Newborn,
pubmed-meshheading:2312410-Ear,
pubmed-meshheading:2312410-Perceptual Distortion,
pubmed-meshheading:2312410-Rats,
pubmed-meshheading:2312410-Sensory Thresholds
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pubmed:year |
1990
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pubmed:articleTitle |
Postnatal development of 2f1-f2 otoacoustic emissions in pigmented rat.
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pubmed:affiliation |
Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, TX 77030.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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