Henson O W, Koplas P A, Keating A W, Huffman R F, Henson M M
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
Hear Res. 1990 Dec;50(1-2):259-73. doi: 10.1016/0378-5955(90)90050-y.
Mustached bats, Pteronotus p. parnellii, use complex, multiharmonic biosonar signals with prominent approx. 60 kHz (CF) components. The sense of hearing is especially acute to sounds near 60 kHz and the cochlea shows a number of specializations in the 60 kHz region. Foremost is a remarkable degree of cochlear resonance. In this study it is shown that: 1) any sounds near the resonance frequency elicit a pronounced resonance that continues after the stimulus terminates; 2) Doppler-shifted echoes of the bat's own cries may cause resonance; 3) continuous resonance can be produced by stimulating the ear with broadband noise but such resonance does not interfere with the bat's ability to Doppler-shift compensate during simulated flight; 4) significant changes in the resonance frequency of the cochlea occur during and after flight; 5) the changes in resonance can be dependent or independent of body temperature changes; and 6) mustached bats continuously adjust the CF component of their pulses to keep the second harmonic echoes in a constant frequency band near the resonance frequency. Thus, mustached bats not only compensate for Doppler-shifts imposed by their movements relative to that of a target, but they cochlear resonance compensate to deal with small changes in the micromechanical properties of the cochlea.
髯蝠，即帕氏油蝠（Pteronotus p. parnellii），会使用复杂的多谐波生物声纳信号，其中突出的约60千赫兹（CF）成分十分显著。其听觉对接近60千赫兹的声音尤为敏锐，并且耳蜗在60千赫兹区域呈现出一些特殊结构。最主要的是具有显著程度的耳蜗共振。在本研究中表明：1）任何接近共振频率的声音都会引发明显的共振，且在刺激终止后仍会持续；2）蝙蝠自身叫声的多普勒频移回声可能引发共振；3）用宽带噪声刺激耳朵可产生持续共振，但这种共振在模拟飞行过程中不会干扰蝙蝠进行多普勒频移补偿的能力；4）飞行期间及飞行后，耳蜗的共振频率会发生显著变化；5）共振的变化可能依赖于或独立于体温变化；6）髯蝠会持续调整其脉冲的CF成分，以使二次谐波回声保持在接近共振频率的恒定频带内。因此，髯蝠不仅能补偿因其相对于目标的运动而产生的多普勒频移，还能通过耳蜗共振来应对耳蜗微机械特性的微小变化。
