Development of wide-band middle ear transmission in the Mongolian gerbil
Development of wide-band middle ear transmission in the Mongolian gerbil
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DOI：
10.1121/1.1420382
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发表时间：
2002-01-01
影响因子：
2.4
通讯作者：
Ruggero, MA
中科院分区：
文献类型：
--
作者：
Overstreet, EH;Ruggero, MA
在深度麻醉的成年和新生（年龄：14至20天）蒙古沙土鼠镫骨振动进行了测量。在成年沙鼠中，镫骨对音调反应的速度大小在整个测量频率范围内（1 kHz至40 kHz）近似恒定。反应阶段指的是鼓膜附近的压力，随着刺激频率的增加而近似线性变化，斜率对应于30 μ s的群延迟。在新生沙鼠中，镫骨对音调的反应灵敏度低于成年人，特别是在中频（例如，在14日龄的沙鼠中，在10-20 kHz下增加约15 dB）。根据镫骨振动和已发表的卵圆窗附近前庭阶压力测量结果计算了成年沙鼠耳蜗的输入阻抗[E。Olson，J. Acoust. Soc. Am. 103. 3445-3463（1998）]，在低于10 kHz的频率下主要是耗散的。结论：（a）成年沙鼠的中耳振动不会限制耳蜗的输入至少达到40 kHz，即，在行为听力图的高频截止的0.5 oct内;和（B）成年和新生沙鼠的结果与质量电抗控制高频听骨振动的假设不一致，并支持中耳起传输线作用的观点。(C)2002年美国声学学会。
Stapes vibrations were measured in deeply anesthetized adult and neonatal (ages: 14 to 20 days) Mongolian gerbils. In adult gerbils, the velocity magnitude of stapes responses to tones was approximately constant over the entire frequency range of measurements, 1to 40 kHz. Response phases referred to pressure near the tympanic membrane varied approximately linearly as a function of increasing stimulus frequency, with a slope corresponding to a group delay of 30 mus. In neonatal gerbils, the sensitivity of stapes responses to tones was lower than in adults, especially at mid-frequencies (e.g., by about 15 dB at 10-20 kHz in gerbils aged 14 days). The input impedance of the adult gerbil cochlea, calculated from stapes vibrations and published measurements of pressure in scala vestibuli near the oval window [E. Olson, J. Acoust. Soc. Am. 103. 3445-3463 (1998)], is principally dissipative at frequencies lower than 10 kHz. Conclusions: (a) middle-ear vibrations in adult gerbils do not limit the input to the cochlea up to at least 40 kHz, i.e.,, within 0.5 oct of the high-frequency cutoff of the behavioral audiogram; and (b) the results in both adult and neonatal gerbils are inconsistent with the hypothesis that mass reactance controls high-frequency ossicular vibrations and support the idea that the middle ear functions as a transmission line. (C) 2002 Acoustical Society of America.