McFadden S L, Walsh E J, McGee J
Developmental Auditory Physiology Laboratory, Boys Town National Research Hospital, Omaha, NE 68131, USA.
Hear Res. 1996 Oct;100(1-2):68-79. doi: 10.1016/0378-5955(96)00108-6.
The ontogeny of auditory function in the Mongolian gerbil (Meriones unguiculatus) was examined by measuring auditory brainstem response (ABR) thresholds for clicks and tone bursts at frequencies between 0.125 and 32 kHz. ABRs were elicited as early as 10 postnatal days (PND) in a small proportion of animals (28.6%). Three phases of development were identified based on the appearance of frequency-threshold curves: (a) an onset period (10-12 PND) during which ABRs could be elicited only by intense stimuli (95-110 dB SPL) within a restricted range of frequencies (0.25-8 kHz); (b) a transition period (13-14 PND) during which thresholds improved but frequency-threshold curves remained relatively flat; and (c) a refinement period (15-30 PND) during which frequency-threshold curves exhibited an adult-like ('V') shape and thresholds improved steadily to adult-like values. Opening of the external auditory meatus was associated with threshold improvements but not with changes in the frequency region of greatest sensitivity. Between the ages of 13 and 21 PND, low-frequency (0.125-1 kHz) and high-frequency (10-32 kHz) thresholds improved at statistically equivalent rates (4.9 and 5.6 dB/day, respectively), while thresholds for mid-frequency stimuli (2-8 kHz) improved at a significantly faster rate of 9.2 dB/day.
通过测量蒙古沙鼠（长爪沙鼠）在0.125至32千赫兹频率范围内对滴答声和短纯音的听觉脑干反应（ABR）阈值，研究了其听觉功能的个体发生。早在出生后10天（PND），一小部分动物（28.6%）就能引出ABR。根据频率阈值曲线的出现确定了三个发育阶段：（a）起始期（10 - 12 PND），在此期间，仅在有限的频率范围（0.25 - 8千赫兹）内，高强度刺激（95 - 110分贝声压级）才能引出ABR；（b）过渡期（13 - 14 PND），在此期间阈值有所改善，但频率阈值曲线仍相对平坦；（c）完善期（15 - 30 PND），在此期间频率阈值曲线呈现出类似成年动物的（“V”）形，阈值稳步提高至类似成年动物的值。外耳道开口与阈值改善相关，但与最敏感频率区域的变化无关。在13至21 PND之间，低频（0.125 - 1千赫兹）和高频（10 - 32千赫兹）阈值以统计学上等效的速率改善（分别为每天4.9分贝和5.6分贝），而中频刺激（2 - 8千赫兹）的阈值以每天9.2分贝的显著更快速率改善。
