Synaptic depression in the localization of sound
Synaptic depression in the localization of sound
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DOI：
10.1038/nature01248
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发表时间：
2003-01-02
期刊：
影响因子：
64.8
通讯作者：
Spain, WJ
中科院分区：
文献类型：
--
作者：
Cook, DL;Schwindt, PC;Spain, WJ
短期突触可塑性在中枢神经系统中很常见，可能有助于时间整合和巧合检测的信号处理功能（1-3）。对于时间积分器，其输出触发率取决于最近突触输入的运行平均值，可塑性调节输入突触强度，因此可以直接控制信号增益(2)和神经网络的功能（1-4）。但是，理想的巧合检测器的触发概率取决于事件的时间巧合，而不是突触事件的平均频率。在这里，我们研究了突触可塑性如何影响时间重合检测的一个具体案例，通过实验表征了小鸡听觉脑干中大细胞核神经元和层状核中重合检测神经元之间突触的突触抑制(5)。我们将这种抑制的经验描述与层状核信号的生物物理模型相结合。由此产生的模型预测，尽管声强相关信息的混淆效应，突触抑制提供了一种自适应机制来保存耳间延时信息（声音在空间中的位置的代理）。这种机制可能有助于层状核神经元将特定的声音定位信息传递给更高的处理中心。
Short-term synaptic plasticity, which is common in the central nervous system, may contribute to the signal processing functions of both temporal integration and coincidence detection(1-3). For temporal integrators, whose output firng rate depends on a running average of recent synaptic inputs, plasticity modulates input synaptic strength and thus may directly control signalling gain(2) and the function of neural networks(1-4). But the firing probability of an ideal coincidence detector would depend on the temporal coincidence of events rather than on the average frequency of synaptic events. Here we have examined a specific case of how synaptic plasticity can affect temporal coincidence detection, by experimentally characterizing synaptic depression at the synapse between neurons in the nucleus magnocellularis and coincidence detection neurons in the nucleus laminaris in the chick auditory brainstem(5). We combine an empirical description of this depression with a biophysical model of signalling in the nucleus laminaris. The resulting model predicts that synaptic depression provides an adaptive mechanism for preserving interaural time-delay information (a proxy for the location of sound in space) despite the confounding effects of sound-intensity-related information. This mechanism may help nucleus laminaris neurons to pass specific sound localization information to higher processing centres.