Cross-Correlations in High-Conductance States of a Model Cortical Network
Cross-Correlations in High-Conductance States of a Model Cortical Network
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DOI：
10.1162/neco.2009.06-08-806
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发表时间：
2010-02-01
影响因子：
2.9
通讯作者：
Hertz, John
中科院分区：
文献类型：
--
作者：
Hertz, John
神经元放电的相关性进行了研究，使用一个简单的网络模型，在一个高电导状态的皮质柱与动态平衡的兴奋和抑制的模拟。虽然个别神经元对之间的相关性表现出相当大的异质性，人口平均值显示系统的行为。当网络处于稳定状态时，平均相关性一般很小，相关系数为1/N阶，其中N是网络中神经元的数量。然而，当网络的输入在时间上变化很大时，会发现更大的值，在这种情况下，网络失去平衡，突触电导很低，而此时正是最强放电发生的时候。然而，突触电流的相关函数的检查表明，在这些突发事件后，通过抑制性突触电导的快速增加，在几毫秒内恢复平衡。这些发现表明平衡状态的概念扩展到包括突触电流的平衡波动，其特征时间尺度为几毫秒。
Neuronal firing correlations are studied using simulations of a simple network model for a cortical column in a high-conductance state with dynamically balanced excitation and inhibition. Although correlations between individual pairs of neurons exhibit considerable heterogeneity, population averages show systematic behavior. When the network is in a stationary state, the average correlations are generically small correlation coefficients are of order 1/N, where N is the number of neurons in the network. However, when the input to the network varies strongly in time, much larger values are found. In this situation, the network is out of balance, and the synaptic conductance is low, at times when the strongest firing occurs. However, examination of the correlation functions of synaptic currents reveals that after these bursts, balance is restored within a few milliseconds by a rapid increase in inhibitory synaptic conductance. These findings suggest an extension of the notion of the balanced state to include balanced fluctuations of synaptic currents, with a characteristic timescale of a few milliseconds.