Rübsamen R, Schäfer M
Zoological Department, University of Kelaniya, Sri Lanka.
J Comp Physiol A. 1990 Dec;167(6):771-84. doi: 10.1007/BF00189767.
Horseshoe bats (Rhinolophus rouxi) were deafened in their 3rd-5th postnatal week. Subsequently their vocalisations were monitored to evaluate the impact of audition on the development of echolocation pulses. Hearing impairment affected the echolocation pulses as follows: the frequency of the constant frequency (CF) component was altered by between +4 kHz and -14 kHz, and the dominance of the second harmonic of the pulses was neutralised by a relative increase in intensity of the first and third harmonics. A second experiment focused on possible influences of acoustical self-stimulation with echolocation pulses on the establishment of auditory fovea representation in the inferior colliculus (IC). Frequency control of echolocation pulses was disrupted by larynx denervation. Thereafter, the bats produced multiharmonic echolocation signals (4-11 harmonics) varying in frequency. IC tonotopy, however, as monitored by stereotaxic electrophysiology, showed the same developmental dynamics as seen in control specimens (Fig. 10). Both experiments indicate that throughout postnatal development echolocation pulses are under auditory feedback control, whereas maturation of the auditory fovea and shifts in its frequency tuning represent an innate process. The significance of this postnatal development might be the adjustment of the vocal motor system of each bat to the frequency of its 'personal' auditory fovea.
菊头蝠（鲁氏菊头蝠）在出生后第3至5周致聋。随后监测它们的发声，以评估听觉对回声定位脉冲发育的影响。听力损伤对回声定位脉冲的影响如下：恒定频率（CF）成分的频率变化在+4千赫兹至-14千赫兹之间，并且脉冲二次谐波的优势因一次谐波和三次谐波强度的相对增加而被抵消。第二个实验聚焦于回声定位脉冲的声学自我刺激对下丘（IC）中听觉中央凹表征建立的可能影响。喉部去神经支配破坏了回声定位脉冲的频率控制。此后，蝙蝠发出频率各异的多谐波回声定位信号（4至11个谐波）。然而，通过立体定位电生理学监测的IC音频定位显示出与对照标本相同的发育动态（图10）。两个实验均表明，在整个出生后发育过程中，回声定位脉冲受听觉反馈控制，而听觉中央凹的成熟及其频率调谐的变化是一个先天过程。这种出生后发育的意义可能在于使每只蝙蝠的发声运动系统适应其“个人”听觉中央凹的频率。
