Spatiotemporal structure of reverberatory bursts in developing cultured networks
Chi-Hsu Huang1, Yu-Ting Huang1,2, Chun-Chung Chen1*, C. K. Chan1,2
1Institute of Physics, Academia Sinica, Taipei, Taiwan
2Department of Physics and Center for Complex Systems, National Central University, Taoyuan, Taiwan
* presenting author:Chun-Chung Chen,
Developing networks of neural systems can exhibit spontaneous, synchronous activities called neural bursts, which are believed to play an important role in the organization of functional neural circuits. Before the network matures, the activity level of a burst can reverberate in repeated rise-and-falls of hundreds of milliseconds following the initial wave-like outbreak of spiking activity, while, the burst itself can last for seconds. To investigate the spatiotemporal structure of the reverberatory bursts, we culture dissociated, rat cortical neurons on high-density multi-electrode array to record dynamics of neural activity over the growth and maturation of the network. We found the synchrony of the spiking significantly reduced following the initial wave of propagation and the activities become broadly distributed spatially. However, the synchrony returns as the system reverberates and increasingly sharper activity peaks are observed until the end of the burst. We also perform computer simulations of the system using a physiologically realistic model in two spatial dimensions. The parameters that successful producing the observed resynchronization of spiking in the bursts suggest a cause in the depletion of synaptic resources. The spatial propagation dynamics of the simulations also match well with observations over the course of a burst, and point to an interplay of the synaptic efficacy and neural self-activation or noise in producing the rich morphology of the observed reverberatory bursts.

Keywords: neuronal networks, multi-electrode array, neural bursts, synchronization dynamics, reverberation