Yamamoto Hideaki, Moriya Satoshi, Ide Katsuya, Hayakawa Takeshi, Akima Hisanao, Sato Shigeo, Kubota Shigeru, Tanii Takashi, Niwano Michio, Teller Sara, Soriano Jordi, Hirano-Iwata Ayumi
WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan.
Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577, Japan.
Sci Adv. 2018 Nov 14;4(11):eaau4914. doi: 10.1126/sciadv.aau4914. eCollection 2018 Nov.
As in many naturally formed networks, the brain exhibits an inherent modular architecture that is the basis of its rich operability, robustness, and integration-segregation capacity. However, the mechanisms that allow spatially segregated neuronal assemblies to swiftly change from localized to global activity remain unclear. Here, we integrate microfabrication technology with in vitro cortical networks to investigate the dynamical repertoire and functional traits of four interconnected neuronal modules. We show that the coupling among modules is central. The highest dynamical richness of the network emerges at a critical connectivity at the verge of physical disconnection. Stronger coupling leads to a persistently coherent activity among the modules, while weaker coupling precipitates the activity to be localized solely within the modules. An in silico modeling of the experiments reveals that the advent of coherence is mediated by a trade-off between connectivity and subquorum firing, a mechanism flexible enough to allow for the coexistence of both segregated and integrated activities. Our results unveil a new functional advantage of modular organization in complex networks of nonlinear units.
与许多自然形成的网络一样，大脑呈现出一种固有的模块化结构，这是其丰富的可操作性、稳健性以及整合-分离能力的基础。然而，使得空间上分离的神经元组件能够迅速从局部活动转变为全局活动的机制仍不清楚。在此，我们将微加工技术与体外皮质网络相结合，以研究四个相互连接的神经元模块的动态特征和功能特性。我们表明模块间的耦合至关重要。网络的最高动态丰富性出现在物理断开边缘的临界连通性处。更强的耦合导致模块间持续的相干活动，而较弱的耦合则使活动仅局限于模块内部。对实验的计算机模拟表明，相干性的出现是由连通性和亚阈值发放之间的权衡介导的，这一机制足够灵活，能够允许分离活动和整合活动同时存在。我们的结果揭示了非线性单元复杂网络中模块化组织的一种新的功能优势。
