PDF(Pubmed)
Abstract：
The auditory brainstem response (ABR) to tone burst stimuli of thirteen frequencies ranging from 0.5 to 48 kHz was recorded in the nine-banded armadillo (Dasypus novemcinctus), the only extant member of the placental mammal superorder Xenarthra in North America. The armadillo ABR consisted of five main peaks that were visible within the first 10 ms when stimuli were presented at high intensities. The latency of peak I of the armadillo ABR increased as stimulus intensity decreased by an average of 20 μs/dB. Estimated frequency-specific thresholds identified by the ABR were used to construct an estimate of the armadillo audiogram describing the mean thresholds of the eight animals tested. The majority of animals tested (six out of eight) exhibited clear responses to stimuli from 0.5 to 38 kHz, and two animals exhibited responses to stimuli of 48 kHz. Across all cases, the lowest thresholds were observed for frequencies from 8 to 12 kHz. Overall, we observed that the armadillo estimated audiogram bears a similar pattern as those observed using ABR in members of other mammalian clades, including marsupials and later-derived placental mammals.
摘要：
在九带状Armadillo（Dasypusnovemcinctus）中记录了对13种频率范围为0.5至48kHz的音调突发刺激的听觉脑干反应（ABR），北美唯一现存的胎盘哺乳动物Xenarthra。ArmadilloABR由五个主峰组成，当以高强度呈现刺激时，在前10ms内可见。随着刺激强度平均降低20μs/dB，ArmadilloABR的峰I的潜伏期增加。由ABR鉴定的估计的频率特异性阈值用于构建Armadillo听力图的估计值，该估计值描述了所测试的八只动物的平均阈值。大多数测试的动物（八分之六）对0.5至38kHz的刺激表现出明显的反应，两只动物对48kHz的刺激表现出反应。在所有案件中，最低阈值为8~12kHz的频率.总的来说,我们观察到，在其他哺乳动物进化枝的成员中使用ABR观察到的Armadillo估计的听力图具有相似的模式，包括有袋动物和后来衍生的胎盘哺乳动物。
