Differential short-term synaptic plasticity and transmission of complex spike trains: to depress or to facilitate?
Differential short-term synaptic plasticity and transmission of complex spike trains: to depress or to facilitate?
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DOI：
10.1093/cercor/10.11.1143
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发表时间：
2000-11-01
期刊：
影响因子：
3.7
通讯作者：
Wang, XJ
中科院分区：
文献类型：
--
作者：
Matveev, V;Wang, XJ
实验研究表明，显著的短期易化和抑制在不同类别的皮质突触上有不同的表达。为了探索突触动力学的计算意义，我们通过一个被赋予短期易化和囊泡耗竭的皮质突触的随机模型来研究复杂的棘波序列的传递。突触模型的输入要么是从表现良好的猴子的视觉和前额叶皮质记录的真实棘波训练数据，要么是用规定的时间统计数字生成的。我们测试了这样一种假设，即短期易化可以使突触过滤掉单个棘波，并有利于动作电位的爆发。我们发现，爆发尖峰和孤立尖峰的释放概率之比随着每个爆发的尖峰数目的增加和孤立尖峰之间的间隔的增加而单调增长。当促进时间常数与平均突发持续时间匹配时，突发检测是最佳的。使用以长期幂规律时间相关性为特征并类似于感觉神经元的分形样棘波模式，我们发现易化在短时间尺度上增加了相关性。相反，抑郁导致所有时间尺度上的时间相关性显著降低，并导致平坦的(白化的)功率谱，从而解除自然输入信号的关联。
Experimental studies have revealed conspicuous short-term facilitation and depression that are expressed differentially at distinct classes of cortical synapses. To explore computational implications of synaptic dynamics, we investigated transmission of complex spike trains through a stochastic model of cortical synapse endowed with short-term facilitation and vesicle depletion. Inputs to the synapse model were either real spike train data recorded from the visual and prefrontal cortices of behaving monkeys, or were generated numerically with prescribed temporal statistics. We tested the hypothesis that short-term facilitation could enable synapses to filter out single spikes and favor bursts of action potentials. We found that the ratio between release probabilities for a burst spike and an isolated spike grows monotonically with increasing number of spikes per burst, and with increasing interval between isolated spikes. Burst detection is optimal when the facilitation time constant matches the average burst duration. Using fractal-like spike patterns characterized by long-term power-law temporal correlations and similar to those seen in sensory neurons, we found that facilitation increases correlation at short time scales. In contrast, depression leads to a dramatic reduction in temporal correlations at all time scales, and to a flat ('whitened') power spectrum, thereby decorrelating natural input signals.