Parham K, Willott J F
Department of Psychology, Northern Illinois University, DeKalb 60115.
Behav Neurosci. 1988 Dec;102(6):881-6. doi: 10.1037//0735-7044.102.6.881.
C57BL/6J (C57) mice demonstrate progressive age-related hearing loss during the first year of life, whereas CBA/J (CBA) mice lose little sensitivity through 18 months of age. The acoustic startle response (ASR) was measured in these strains to determine behavioral correlates of aging with and without presbycusis. The stimuli were tone pips (10-ms duration, 1-ms rise-fall) with frequencies of 4, 8, 12, 16, or 24 kHz at intensities of 70, 80, 90, or 100 dB SPL. ASR "thresholds" (the minimum SPL required to elicit ASRs more than 50% of the time) increased with age, and startle amplitudes became smaller in both strains. However, the changes in these startle parameters were much more pronounced in C57 mice, with middle to high frequencies (12-24 kHz) severely affected. The startle latencies at and above ASR "threshold" increased with age in C57 mice, but did not change in CBA mice. The CBA data indicate that aging, per se, has little effect on ASR parameters; the C57 data show that hearing loss is a cogent factor. However, ASR parameters of C57 mice are altered to a greater extent than expected, on the basis of the elevations of absolute sensory thresholds, particularly for middle frequencies (12-16 kHz). Both peripheral and central mechanisms are proposed to account for the discrepancy.
C57BL/6J（C57）小鼠在出生后的第一年表现出与年龄相关的渐进性听力损失，而CBA/J（CBA）小鼠在18个月大时听力敏感度几乎没有下降。测量了这些品系小鼠的听觉惊吓反应（ASR），以确定有或无老年性耳聋情况下衰老与行为之间的关联。刺激声为短纯音（持续时间10毫秒，上升-下降时间1毫秒），频率分别为4、8、12、16或24千赫，强度分别为70、80、90或100分贝声压级。ASR“阈值”（引发ASR超过50%时间所需的最小声压级）随年龄增加，且两个品系小鼠的惊吓幅度均变小。然而，这些惊吓参数的变化在C57小鼠中更为明显，中高频（12 - 24千赫）受到严重影响。在C57小鼠中，ASR“阈值”及以上的惊吓潜伏期随年龄增加，但在CBA小鼠中没有变化。CBA的数据表明，衰老本身对ASR参数影响很小；C57的数据表明听力损失是一个重要因素。然而，基于绝对感觉阈值的升高，特别是中频段（12 - 16千赫），C57小鼠的ASR参数变化程度比预期更大。外周和中枢机制都被认为可以解释这种差异。
