Baruchi Itay, Volman Vladislav, Raichman Nadav, Shein Mark, Ben-Jacob Eshel
School of Physics & Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
Eur J Neurosci. 2008 Nov;28(9):1825-35. doi: 10.1111/j.1460-9568.2008.06487.x.
We have studied the emergence of mutual synchronization and activity propagation in coupled neural networks from rat cortical cells grown on a micro-electrode array for parallel activity recording of dozens of neurons. The activity of each sub-network by itself is marked by the formation of synchronized bursting events (SBE) - short time windows of rapid neuronal firing. The joint activity of two coupled networks is characterized by the formation of mutual synchronization, i.e. the formation of SBE whose activity starts at one sub-network and then propagates to the other. The sub-networks switch roles in initiating the mutual SBE. However, spontaneous propagation (initiation) asymmetry emerges - one of the sub-networks takes on the role of initiating substantially more mutual SBE than the other, despite the fact that the two are engineered to be similar in size and cell density. Analysis of the interneuron correlations in the SBE also reveals the emergence of activity (function) asymmetry - one sub-network develops a more organized structure of correlations. We also show activity propagation and mutual synchronization in four coupled networks. Using computer simulations, we propose that the function asymmetry reflects asymmetry between the internal connectivity of the two networks, whereas the propagation asymmetry reflects asymmetry in the connectivity between the sub-networks. These results agree with the experimental findings that the initiation and function asymmetry can be separately regulated, which implies that information transfer (activity propagation) and information processing (function) can be regulated separately in coupled neural networks.
我们研究了在微电极阵列上生长的大鼠皮质细胞耦合神经网络中相互同步和活动传播的出现情况，该微电极阵列用于并行记录数十个神经元的活动。每个子网络自身的活动以同步爆发事件（SBE）的形成为标志，即神经元快速放电的短时间窗口。两个耦合网络的联合活动以相互同步的形成为特征，即SBE的形成，其活动始于一个子网络，然后传播到另一个子网络。子网络在启动相互SBE时会切换角色。然而，自发传播（启动）不对称出现了——尽管两个子网络在大小和细胞密度上设计得相似，但其中一个子网络承担启动相互SBE的次数比另一个子网络多得多。对SBE中中间神经元相关性的分析还揭示了活动（功能）不对称的出现——一个子网络发展出更有组织性的相关性结构。我们还展示了四个耦合网络中的活动传播和相互同步。通过计算机模拟，我们提出功能不对称反映了两个网络内部连接性之间的不对称，而传播不对称反映了子网络之间连接性的不对称。这些结果与实验结果一致，即启动和功能不对称可以分别调节，这意味着在耦合神经网络中信息传递（活动传播）和信息处理（功能）可以分别调节。
