Influence of inhibitory inputs on rate and timing of responses in the anteroventral cochlear nucleus
Influence of inhibitory inputs on rate and timing of responses in the anteroventral cochlear nucleus
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DOI：
10.1152/jn.00708.2007
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发表时间：
2008-03-01
影响因子：
2.5
通讯作者：
Carney, Laurel H.
中科院分区：
文献类型：
--
作者：
Gai, Yan;Carney, Laurel H.
解剖学和生理学研究表明，前腹侧耳蜗核(AVCN)神经元接受甘氨酸能和GABA能抑制性输入。本研究分析了阻断抑制后AVCN神经元对纯音和复杂音时间反应的变化。阻断抑制影响各类型AVCN神经元的时程反应。阻断抑制后，斩波峰增多，斩波周期缩短。持续和缓慢适应的斩波在阻断抑制后的反应持续时间内表现出规律性增加，而大多数短暂性斩波在反应的早期表现出规律性增加。在原发样反应和异常反应的神经元中观察到不同的时间反应模式的变化，几个神经元在阻断抑制后显示出第一峰潜伏期的大幅缩短。这一结果与之前的研究结果不一致，即通过操纵抑制对开始反应的影响小于对持续反应的影响。虽然阻断抑制对自发活动的影响大于对纯音诱发活动的影响，但由于变异性较大，自发活动的变化不那么显著。此外，对于相对较高水平的掩蔽噪声，阻断抑制对单独噪声和噪声加音调刺激的反应具有相似的影响，这与先前对低水平背景噪声的研究相反。总体而言，抑制只有对调幅音调的反应有增强时间对比度的效果，包络同步性增强。这项研究的结果为AVCN神经元接收的抑制性输入的特征、功能作用和可能的来源提供了新的信息。
Anatomical and physiological studies have shown that anteroventral cochlear nucleus ( AVCN) neurons receive glycinergic and GABAergic inhibitory inputs. In this study, changes in the temporal responses of AVCN neurons to pure tones and complex sounds after blocking inhibition were analyzed. Blocking inhibition influenced the temporal responses of each type of AVCN neuron. Choppers showed more chopping peaks and shortened chopping cycles after blocking inhibition. Sustained and slowly adapting choppers showed increased regularity throughout the response duration after blocking inhibition, whereas most transient choppers showed increased regularity in the early part of the response. Diverse changes in temporal response patterns were observed in neurons with primary-like and unusual responses, with several neurons showing a large decrease in the first-spike latency after blocking inhibition. This result disagreed with previous findings that onset responses are less affected than sustained responses by manipulating inhibition. Although blocking inhibition had a greater effect on spontaneous activity than that on tone-evoked activity, the change in spontaneous activity was less significant because of larger variability. In addition, for relatively high level masker noises, blocking inhibition had similar effects on responses to noise-alone and noise-plus-tone stimuli, in contrast with previous studies with low-level background noise. In general, inhibition had an enhancing effect on temporal contrast only for responses to amplitude-modulated tones, for which envelope synchrony was enhanced. Results of this study contribute new information about the characteristics, functional roles, and possible sources of inhibitory inputs received by AVCN neurons.