Tympanal mechanics and neural responses in the ears of a noctuid moth.
Tympanal mechanics and neural responses in the ears of a noctuid moth.
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夜蛾耳朵的鼓膜力学和神经反应。
DOI：
10.1007/s00114-011-0851-7
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Ter Hofstede HM
中科院分区：
文献类型：
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作者：
Ter Hofstede HM
许多飞蛾进化出耳朵来探测掠食性蝙蝠的回声定位呼叫。尽管几十年来人们对蝙蝠检测的神经生理学进行了深入研究，但声音诱导的夜蛾鼓膜运动与听觉感觉细胞（A1和A2）动作电位之间的关系却很少受到关注。使用激光多普勒振动仪，我们测量了完整或准备用于神经记录的飞蛾的鼓室响应纯音脉冲的速度和位移。当从听神经记录时，鼓室在神经阈值处的位移在不同频率下保持不变，而速度随频率而变化。这表明夜蛾感觉细胞中触发动作电位的关键生物物理参数是鼓室位移，而不是速度。蛾听力神经生理学研究的有效性建立在解剖和记录过程不影响耳朵生物力学的假设之上。当飞蛾完好无损或准备对接近神经阈值的声音水平进行神经记录时，鼓室速度或位移没有一致的差异，这表明这项研究和其他神经生理学研究为完整的飞蛾在阈值下听到的声音提供了很好的估计。
Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement, not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold.