Bursting activity interplay in modular neural networks in vitro

Neural networks modularity is a major challenge to study spiking pattern propagation and information processing in the brain. Sparse and heterogeneous connectivity between network modules defines spiking activity generation and interplay. Detailed study of modular network complex connectivity and dynamics is complicated by inducing retrograde or closed-loop activity. In this study, we analyzed the spiking activity of spontaneous and stimulus-induced interplay between two cultured neuronal networks (source-target) coupled with unidirectional synaptic connections, which were formed by microfluidic microchannels. Inhibition of excitatory synaptic activity in a source module abolished retrograde and closed-loop activity in the interplay. We found characteristics of electrical stimulation applied to the intermodular connections, which evoked a network-wide response in a target module. The developed approach can be applied to study synaptic plasticity in modular networks in vitro and improvement of new methods of neurointerface design.