Sinnott J M, Street S L, Mosteller K W, Williamson T L
Psychology Department, University of South Alabama, Mobile 36688, USA.
Hear Res. 1997 Oct;112(1-2):235-46. doi: 10.1016/s0378-5955(97)00125-1.
Absolute thresholds for complex vowel stimuli were compared in Mongolian gerbils (Meriones unguiculatus) as a function of age and genetic origin. For a group of 12-month-old 'domestic' gerbils obtained from Tumblebrook Farms, lowest thresholds averaging 14 dB SPL occurred for the vowel /alpha/, which had its most intense formant (F1) at 730 Hz. Thresholds increased to 22 dB SPL for /i/, which had its two most intense formants (F1 and F3) at 270 and 3000 Hz, respectively. Highest thresholds of 30 dB SPL occurred for /u/, which had its most intense formant (F1) at 300 Hz. Thresholds increased by about 10 dB per year through the ages of 12-36 months, with most of the loss occurring for /alpha/ and /u/. The domestic gerbils' /alpha/ thresholds corresponded well to those measured in aging gerbils in electrophysiological studies. Vowel thresholds were also measured in a group of first-generation offspring of 'wild' gerbils imported from Asia, first tested at the ages of 18-24 months. Thresholds were similar to those of the 12-month-old domestic gerbils, and showed no hearing loss with age up to 36 months. The wild gerbils were also free of ear impactions, which commonly occurred in the domestic gerbils. The hearing loss with age in the domestic gerbils may have a genetic basis, and might be due to inbreeding in the domestic strain, in contrast to the hybrid vigor of the wild gerbils.
研究比较了蒙古沙鼠（长爪沙鼠）对复合元音刺激的绝对阈值与年龄和遗传起源的关系。对于一组从Tumblebrook农场获得的12个月大的“家养”沙鼠，元音/α/的最低阈值平均为14 dB SPL，其最强共振峰（F1）在730 Hz。/i/的阈值增加到22 dB SPL，其两个最强共振峰（F1和F3）分别在270 Hz和3000 Hz。/u/的最高阈值为30 dB SPL，其最强共振峰（F1）在300 Hz。在12至36个月的年龄段中，阈值每年增加约10 dB，大部分损失发生在/α/和/u/上。家养沙鼠的/α/阈值与电生理研究中老龄沙鼠测量的阈值非常吻合。还测量了一组从亚洲进口的“野生”沙鼠的第一代后代的元音阈值，它们在18至24个月大时首次接受测试。阈值与12个月大的家养沙鼠相似，在36个月龄之前未显示出听力损失。野生沙鼠也没有耳部堵塞问题，而这在家养沙鼠中很常见。家养沙鼠随年龄增长出现的听力损失可能有遗传基础，可能是由于家养品系的近亲繁殖，与野生沙鼠的杂种优势形成对比。
