Huffman R F, Henson O W
Curriculum in Neurobiology, University of North Carolina, Chapel Hill.
J Comp Physiol A. 1993 Jan;171(6):725-34. doi: 10.1007/BF00213069.
The cochlea of the mustached bat (Pteronotus parnellii) has sharp tuning characteristics and pronounced resonance within a narrow band near the second harmonic, constant frequency (CF2) component of the animal's biosonar signals. That fine frequency discrimination occurs within this narrow band is evident from Doppler-shift compensation, whereby bats in flight lower the frequency of emitted CF2s to maintain returning echoes within this band. This study examined various factors capable of producing shifts in both the cochlear resonance frequency (CRF) and CF2s emitted by stationary bats and bats actively Doppler-shift compensating on a pendulum. Each of three experimental factors shifted the CRF in a reversible manner. Changes in body temperature produced an average CRF shift of 39 +/- 18 Hz/degrees C. The CRF increased with flight by 150 +/- 100 Hz and returned to baseline values within 10 min after flight. Contralateral sound exposure produced smaller (100 +/- 20 Hz), rapid shifts in the CRF, suggesting that a mechanism different from the temperature- and flight-related shifts was involved. Changes in the CRF induced by temperature and flight were accompanied by shifts in the emitted CF2 of stationary and moving bats. Coupled with a companion study of associated shifts in neural tuning, the concomitant changes in CRF and CF2 provide evidence of cochlear tuning lability in the mustached bat.
髯蝠（Pteronotus parnellii）的耳蜗具有敏锐的调谐特性，并且在动物生物声纳信号的二次谐波、恒定频率（CF2）成分附近的窄带内有明显的共振。从多普勒频移补偿可以明显看出，在这个窄带内发生了精细的频率辨别，即飞行中的蝙蝠会降低发射的CF2频率，以使返回的回声保持在这个频段内。本研究考察了各种能够使静止蝙蝠以及在钟摆上进行主动多普勒频移补偿的蝙蝠所发出的耳蜗共振频率（CRF）和CF2发生偏移的因素。三个实验因素中的每一个都以可逆的方式使CRF发生了偏移。体温变化导致CRF平均偏移39±18赫兹/摄氏度。飞行时CRF增加了150±100赫兹，并在飞行后10分钟内恢复到基线值。对侧声音暴露使CRF产生了较小（100±20赫兹）、快速的偏移,这表明涉及到一种与温度和飞行相关偏移不同的机制。温度和飞行引起的CRF变化伴随着静止和移动蝙蝠所发射CF2的偏移。结合一项关于神经调谐相关偏移的配套研究，CRF和CF2的同步变化为髯蝠耳蜗调谐的不稳定性提供了证据。
