LABILE COCHLEAR TUNING IN THE MOUSTACHED BAT .2. CONCOMITANT SHIFTS IN NEURAL TUNING
LABILE COCHLEAR TUNING IN THE MOUSTACHED BAT .2. CONCOMITANT SHIFTS IN NEURAL TUNING
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DOI：
10.1007/bf00213070
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发表时间：
1993-01-01
期刊：
影响因子：
--
通讯作者：
HENSON, OW
中科院分区：
文献类型：
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作者：
HUFFMAN, RF;HENSON, OW
接近60千赫的声音刺激会在髭须蝠（Pteronotus parnellii parnellii）的耳蜗中引起明显的共振。耳蜗共振频率（CRF）接近蝙蝠生物声纳信号的二次谐波、恒频（CF2）分量。在保持CF2和三次谐波（CF3）回声的窄带内，耳蜗具有在整个中央听觉系统中保存的尖锐调谐特性。本研究的目的是研究CRF的温度相关变化对耳蜗核和下丘神经元调谐特性的影响。对6只长期植入耳蜗麦克风电极的清醒蝙蝠进行了82个单单元和多单元记录。当CRF随体温变化时，神经元的调谐曲线急剧调整到CF2和CF3附近的频率，在每种情况下都随着CRF的变化而变化，从而产生单元最佳频率的变化。结果表明，小胡子蝙蝠的耳蜗调谐是不稳定的，这种不稳定性导致中央听觉神经元频率响应的张力移位。此外，研究结果还提供了耳蜗CF2和CF3区域内频率对位置编码发生变化的证据。结合生物声纳发射频率和CRF随温度和飞行而变化的发现，我们得出结论，生物声纳信号的调整适应了主动回声定位时发生的耳蜗和神经调谐的变化。
Acoustic stimuli near 60 kHz elicit pronounced resonance in the cochlea of the mustached bat (Pteronotus parnellii parnellii). The cochlear resonance frequency (CRF) is near the second harmonic, constant frequency (CF2) component of the bat's biosonar signals. Within narrow bands where CF2 and third harmonic (CF3) echoes are maintained, the cochlea has sharp tuning characteristics that are conserved throughout the central auditory system. The purpose of this study was to examine the effects of temperature-related shifts in the CRF on the tuning properties of neurons in the cochlear nucleus and inferior colliculus.Eighty-two single and multi-unit recordings were characterizedin 6 awake bats with chronically implanted cochlear microphonic electrodes. As the CRF changed with body temperature, the tuning curves of neurons sharply tuned to frequencies near the CF2 and CF3 shifted with the CRF in every case, yielding a change in the unit's best frequency. The results show that cochlear tuning is labile in the mustached bat, and that this lability produces tonotopic shifts in the frequency response of central auditory neurons. Furthermore, results provide evidence of shifts in the frequency-to-place code within the sharply tuned CF2 and CF3 regions of the cochlea. In conjunction with the finding that biosonar emission frequency and the CRF shift concomitantly with temperature and flight, it is concluded that the adjustment of biosonar signals accommodates the shifts in cochlear and neural tuning that occur with active echolocation.