Size-dependent regulation of synchronized activity in living neuronal networks

作者：Yamamoto Hideaki^*; Kubota Shigeru; Chida Yudai; Morita Mayu; Moriya Satoshi; Akima Hisanao; Sato Shigeo; Hirano Iwata Ayumi; Tanii Takashi; Niwano Michio

来源：Physical Review E, 2016, 94(1): 012407.

DOI：10.1103/PhysRevE.94.012407

We study the effect of network size on synchronized activity in living neuronal networks. Dissociated cortical neurons form synaptic connections in culture and generate synchronized spontaneous activity within 10 days in vitro. Using micropatterned surfaces to extrinsically control the size of neuronal networks, we show that synchronized activity can emerge in a network as small as 12 cells. Furthermore, a detailed comparison of small (similar to 20 cells), medium (similar to 100 cells), and large (similar to 400 cells) networks reveal that synchronized activity becomes destabilized in the small networks. A computational modeling of neural activity is then employed to explore the underlying mechanism responsible for the size effect. We find that the generation and maintenance of the synchronized activity can be minimally described by: (1) the stochastic firing of each neuron in the network, (2) enhancement in the network activity in a positive feedback loop of excitatory synapses, and (3) Ca-dependent suppression of bursting activity. The model further shows that the decrease in total synaptic input to a neuron that drives the positive feedback amplification of correlated activity is a key factor underlying the destabilization of synchrony in smaller networks. Spontaneous neural activity plays a critical role in cortical information processing, and our work constructively clarifies an aspect of the structural basis behind this.

• 出版日期2016-7-13