Spike-driven synaptic dynamics generating working memory states
Spike-driven synaptic dynamics generating working memory states
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DOI：
10.1162/089976603321192086
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发表时间：
2003-03-01
影响因子：
2.9
通讯作者：
Mongillo, G
中科院分区：
文献类型：
--
作者：
Amit, DJ;Mongillo, G
研究了网络的集体行为，模拟了由塑料突触连接的尖峰神经元的皮质模块。在一个由尖峰神经元组成的大型网络中模拟了一个详细的尖峰驱动的突触动力学，实现了神经元和突触的完全双重动力学。一组外部刺激的重复呈现被证明是为了将网络结构构建到维持工作记忆的点(选择性延迟活动)。当在功能定义的群体中分析突触动力学作为突触前和突触后峰率的函数时，它揭示了Hebbian可塑性范式的一个新的变体：在神经元对之间的任何突触功能集(例如，刺激刺激、刺激延迟、刺激自发)中，存在增强和抑制的有限概率。这导致在这两个概率的比率水平上的增强或抑制饱和。当两个概率中的一个概率相对于另一个概率非常高时，熟悉的Hebbian机制被恢复。但是，在形成相关工作记忆的地方，它可以防止过度学习。与所获得的突触结构的稳定性和允许构建的全局活动机制相关的约束用描述单个突触动力学的参数来表示。根据实验观察到的准确的棘波计时效应和相关的生物学可信问题，对突触动力学进行了讨论。
The collective behavior of a network, modeling a cortical module of spiking neurons connected by plastic synapses is studied. A detailed spike-driven synaptic dynamics is simulated in a large network of spiking neurons, implementing the full double dynamics of neurons and synapses. The repeated presentation of a set of external stimuli is shown to structure the network to the point of sustaining working memory (selective delay activity). When the synaptic dynamics is analyzed as a function of pre- and postsynaptic spike rates in functionally defined populations, it reveals a novel variation of the Hebbian plasticity paradigm: in any functional set of synapses between pairs of neurons (e.g., stimulated-stimulated, stimulated-delay, stimulated-spontaneous), there is a finite probability of potentiation as well as of depression. This leads to a saturation of potentiation or depression at the level of the ratio of the two probabilities. When one of the two probabilities is very high relative to the other, the familiar Hebbian mechanism is recovered. But where correlated working memory is formed, it prevents overlearning. Constraints relevant to the stability of the acquired synaptic structure and the regimes of global activity allowing for structuring are expressed in terms of the parameters describing the single-synapse dynamics. The synaptic dynamics is discussed in the light of experiments observing precise spike timing effects and related issues of biological plausibility.