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首页> 外文期刊>Journal of Neurophysiology >Models of neuronal transient synchrony during propagation of activity through neocortical circuitry.
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Models of neuronal transient synchrony during propagation of activity through neocortical circuitry.

机译：通过新皮层回路传播活动期间的神经元瞬时同步模型。

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Stereotypic paroxysmal discharges that propagate in neocortical tissues after electrical stimulations are used as a probe for studying cortical circuitry. I use modeling to investigate the effects of sparse connectivity, heterogeneity of intrinsic neuronal properties, and synaptic noise on synchronization of evoked propagating neuronal discharges in a network of excitatory, regular spiking neurons with spatially decaying connectivity. The global coherence of the traveling discharge is characterized by the correlation function between spike trains of neurons, averaged over all the pairs of neurons in the system at the same distance. Local coherence of two neurons is characterized by their correlation function averaged over many trials or, for persistent activity, over a long time interval. Spike synchronization between neurons emerges as a result of the transient activity; if activity is persistent, there is no synchrony, and cross-correlation functions are flat. During discharge propagation, system-average cross-correlation between neurons does not depend on their mutual distance except for a time shift. Spike synchronization occurs only when the average number of synapses M a cell receives is large enough. As M increases, there is a cross-over from an asynchronized to a synchronized discharge. Synaptic depression appears to help synchrony; it reduces the M value at the cross-over. The strengths of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) conductances affect synchrony only weakly. Spike synchronization is robust even with large levels of heterogeneity. Synaptic noise reduces synchrony, but strong synchrony is observed at a noise level that cannot evoke spontaneous discharges. System-average spike synchronization is determined by the levels of sparseness, heterogeneity, and noise, whereas trial-average spike synchronization is determined only by the noise level. Therefore, I predict that experiments will reveal local, two-cell spike synchrony, but not global synchrony.
机译：在电刺激后在新皮层组织中传播的定型阵发性放电被用作研究皮层电路的探针。我使用模型来研究稀疏连通性，内在神经元特性的异质性和突触噪声对具有空间衰减连通性的兴奋性，规则峰值神经元网络中诱发的传播神经元放电同步的影响。行进放电的整体相干性以神经元的尖峰序列之间的相关函数为特征，该函数在系统中所有相同距离的成对神经元对上平均。两个神经元的局部相干性的特征在于，它们的相关函数在许多试验中均是平均的，或者对于长时间的活动而言，其持续时间较长。神经元之间的突波同步是瞬时活动的结果。如果活动是持久的，则没有同步，并且互相关函数是平坦的。在放电传播期间，神经元之间的系统平均互相关不依赖于它们之间的相互距离，除了时移。尖峰同步仅在一个单元格收到的平均突触数M足够大时发生。随着M的增加，存在从异步放电到同步放电的过渡。突触抑制似乎有助于同步。它降低了交叉点的M值。 α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）和N-甲基-D-天门冬氨酸（NMDA）的强度仅对同步产生微弱的影响。即使存在大量异质性，峰值同步也很健壮。突触噪声会降低同步性，但是在无法引起自发放电的噪声水平上会观察到强烈的同步性。系统平均尖峰同步由稀疏性，异质性和噪声的级别确定，而试验平均尖峰同步仅由噪声级别确定。因此，我预测实验将揭示局部的两单元尖峰同步，而不是全局同步。

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