Burkard Robert F, Finneran James J, Mulsow Jason
Department of Rehabilitation Science, University at Buffalo, 626 Kimball Tower, Buffalo, New York 14214, USA.
U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, California 92152, USA.
J Acoust Soc Am. 2017 May;141(5):3396. doi: 10.1121/1.4983447.
Rate manipulations can be used to study adaptation processes in the auditory nerve and brainstem. For this reason, rate effects on the click-evoked auditory brainstem response (ABR) have been investigated in many mammals, including humans. In this study, click-evoked ABRs were obtained in eight bottlenose dolphins (Tursiops truncatus) while varying stimulus rate using both conventional averaging and maximum length sequences (MLSs), which allow disentangling ABRs that overlap in time and thus permit the study of adaptation at high rates. Dolphins varied in age and upper cutoff frequency of hearing. Conventional stimulation rates were 25, 50, and 100 Hz and average MLS rates were approximately 50, 100, 250, 500, 1000, 2500, and 5000 Hz. Click peak-equivalent sound pressure levels for all conditions were 135 dB re 1 μPa. ABRs were observed in all dolphins, at all stimulus rates. With increasing rate, peak latencies increased and peak amplitudes decreased. There was a trend for an increase in the interwave intervals with increasing rate, which appeared more robust for the dolphins with a full range of hearing. For those rates where ABRs were obtained for both conventional and MLS approaches, the latencies of the mean data were in good agreement.
速率操纵可用于研究听神经和脑干的适应过程。因此，包括人类在内的许多哺乳动物都对速率对短声诱发的听觉脑干反应（ABR）的影响进行了研究。在本研究中，对8只宽吻海豚（瓶鼻海豚）进行短声诱发ABR检测，同时使用传统平均法和最大长度序列（MLS）改变刺激速率，MLS能够分离出时间上重叠的ABR，从而允许在高速率下研究适应性。海豚的年龄和听力上限频率各不相同。传统刺激速率为25、50和100Hz，平均MLS速率约为50、100、250、500、1000、2500和5000Hz。所有条件下短声的峰值等效声压级均为135dB re 1μPa。在所有刺激速率下，所有海豚均观察到ABR。随着速率增加，峰潜伏期延长，峰振幅降低。随着速率增加，波间期有增加的趋势，对于听力范围完整的海豚，这种趋势似乎更明显。对于通过传统方法和MLS方法均获得ABR的那些速率，平均数据的潜伏期吻合良好。
