Modulation of Excitatory Synaptic Coupling Facilitates Synchronization and Complex Dynamics in a Nonlinear Model of Neuronal Dynamics

We study complex dynamical synchronization in a nonlinear model of a neural system constituted by local networks of densely interconnected excitatory and inhibitory neurons. Neural dynamics are determined by voltage- and ligand-gated ion channels. Coupling between the local networks is introduced via sparse excitatory to excitatory connectivity. It is shown that with modulation of this long-range synaptic coupling, the system undergoes a transition from independent oscillations to stable chaotic synchronization. Between these states exists a ‘weakly' stable state with epochs of synchronization and complex intermittent desynchronization. This may facilitate adaptive brain function by engendering a diverse repertoire of dynamics and contribute to the genesis of complexity in the EEG