Cho Myoung Won, Choi M Y
BK21 Frontier Physics Research Division, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
Phys Rev Lett. 2007 Nov 16;99(20):208102. doi: 10.1103/PhysRevLett.99.208102. Epub 2007 Nov 13.
It is commonly believed that spike timings of a postsynaptic neuron tend to follow those of the presynaptic neuron. Such orthodromic firing may, however, cause a conflict with the functional integrity of complex neuronal networks due to asymmetric temporal Hebbian plasticity. We argue that reversed spike timing in a synapse is a typical phenomenon in the cortex, which has a stabilizing effect on the neuronal network structure. We further demonstrate how the firing causality in a synapse is perturbed by synchronous neural activity and how the equilibrium property of spike-timing dependent plasticity is determined principally by the degree of synchronization. Remarkably, even noise-induced activity and synchrony of neurons can result in equalization of synaptic efficacy.
人们普遍认为，突触后神经元的尖峰时间往往跟随突触前神经元的尖峰时间。然而，由于不对称的时间赫布可塑性，这种顺向发放可能会与复杂神经元网络的功能完整性产生冲突。我们认为，突触中尖峰时间的反转是皮层中的一种典型现象，它对神经元网络结构具有稳定作用。我们进一步证明了突触中的发放因果关系是如何受到同步神经活动的干扰，以及尖峰时间依赖可塑性的平衡特性主要是如何由同步程度决定的。值得注意的是，即使是噪声诱导的神经元活动和同步也会导致突触效能的均衡。
