Behrend O, Kössl M, Schuller G
Zoologisches Institut der Ludwig-Maximilians-Universität München, Germany.
J Comp Physiol A. 1999 Dec;185(6):529-38. doi: 10.1007/s003590050413.
The flying horseshoe bat Rhinolophus rouxi compensates for Doppler shifts in echoes of their orientation pulses. By lowering the frequency of subsequent calls the echo's constant frequency is stabilized at the so-called reference frequency centered in a narrow and sensitive cochlear filter. This audio-vocal behaviour is known as Doppler shift compensation. To investigate whether the bats depend on binaural cues when compensating, three animals were tested for compensation on a swing before and after unilateral deafening. In each case compensation was severely impaired by unilateral deafening. Individual animals' compensation amplitude was reduced to 28-48% of the preoperational compensation of a +1.8 kHz shift. Doppler shift compensation performance did not recover to control levels during the observed period of 24 h after surgery. In contrast, unilateral middle ear removal which induces a unilateral auditory threshold increase of 9-14 dB does not impair compensation performance on the swing. To mimick Doppler shifts in a fixed setup, the frequencies of recorded echolocation calls were experimentally shifted between 0 and +2 kHz and played back via earphones to six animals. The bats completely compensated the experimental shifts only as long as the interaural intensity difference of the playback did not exceed 20 dB. No animal compensated with monaural playback.
鲁氏菊头蝠（Rhinolophus rouxi）能够补偿其定向脉冲回声中的多普勒频移。通过降低后续叫声的频率，回声的恒定频率会稳定在一个以狭窄且敏感的耳蜗滤波器为中心的所谓参考频率上。这种听觉 - 发声行为被称为多普勒频移补偿。为了研究蝙蝠在进行补偿时是否依赖双耳线索，对三只动物在单侧致聋前后在秋千上进行了补偿测试。在每种情况下，单侧致聋都会严重损害补偿能力。个体动物的补偿幅度降低到术前对 +1.8 kHz 频移补偿的 28% - 48%。在术后观察的 24 小时内，多普勒频移补偿性能未恢复到对照水平。相比之下，单侧中耳切除会导致单侧听觉阈值升高 9 - 14 dB，但不会损害在秋千上的补偿性能。为了在固定装置中模拟多普勒频移，将记录的回声定位叫声的频率在 0 到 +2 kHz 之间进行实验性偏移，并通过耳机播放给六只动物。只有当回放的双耳强度差不超过 20 dB 时，蝙蝠才能完全补偿实验性频移。没有动物能通过单耳回放进行补偿。
