Effects of Efferent Activity on Hair Bundle Mechanics
Effects of Efferent Activity on Hair Bundle Mechanics
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DOI：
10.1523/jneurosci.1312-19.2020
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发表时间：
2020-02
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影响因子：
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通讯作者：
Chia-Hsi Jessica Lin;D. Bozovic
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文献类型：
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作者：
Chia-Hsi Jessica Lin;D. Bozovic
听觉和前庭系统的毛细胞都接受传出神经支配。许多先前的研究表明，传出调节用于降低听觉系统的整体灵敏度。传出通路被认为通过调节毛细胞的膜电位来影响毛细胞的敏感性和频率选择性。然而，其对毛细胞的机械响应的影响尚未建立。我们探讨了传出神经元的刺激如何影响单个发束的机械反应性。我们对两种性别的美国牛蛙球囊中的毛细胞体外制备物进行了测试。传出刺激通常导致在刺激的持续时间内的发束自发振荡的频率立即增加。增大刺激幅度和脉冲长度，或相反，减小脉冲间隔导致振荡抑制。此外，我们测试了传出对机械刺激的毛束反应的影响。感受野地图的毛细胞进行传出驱动表现出整体脱敏相对于那些未受刺激的细胞。意义陈述传出系统是听觉系统功能的重要助手。它被认为有助于声音检测和定位，耳毒性预防和言语理解。虽然测量表明，传出抑制基底膜运动，仍然有很多未知的传出活动如何影响听力力学。在这里，我们探索传出系统的能力在毛束水平的机械基础。我们目前的光学记录，感受野地图，和敏感性曲线，显示一个发束是脱敏传出刺激。这支持了传出调节可能是调节毛束机械敏感性的生物控制参数的假设。
Hair cells in both the auditory and vestibular systems receive efferent innervation. A number of prior studies have indicated that efferent regulation serves to diminish the overall sensitivity of the auditory system. The efferent pathway is believed to affect the sensitivity and frequency selectivity of the hair cell by modulating its membrane potential. However, its effect on the mechanical response of the hair cell has not been established. We explored how stimulation of the efferent neurons affects the mechanical responsiveness of an individual hair bundle. We tested this effect on in vitro preparations of hair cells in the sacculi of American bullfrogs of both genders. Efferent stimulation routinely resulted in an immediate increase of the frequency of hair bundle spontaneous oscillations for the duration of the stimulus. Enlarging the stimulus amplitude and pulse length, or conversely, decreasing the interpulse interval led to oscillation suppression. Additionally, we tested the effects of efference on the hair bundle response to mechanical stimulation. The receptive field maps of hair cells undergoing efferent actuation demonstrated an overall desensitization with respect to those of unstimulated cells. SIGNIFICANCE STATEMENT The efferent system is an important aide for the performance of the auditory system. It has been seen to contribute to sound detection and localization, ototoxicity prevention, and speech comprehension. Although measurements have demonstrated that efference suppresses basilar membrane movement, there is still much unknown about how efferent activity affects hearing mechanics. Here, we explore the mechanical basis for the efferent system's capabilities at the level of the hair bundle. We present optical recordings, receptive field maps, and sensitivity curves that show a hair bundle is desensitized by efferent stimulation. This supports the hypothesis that efferent regulation may be a biological control parameter for tuning the hair bundle's mechanical sensitivity.