Modulation of excitatory synaptic coupling facilitates synchronization and complex dynamics in a biophysical model of neuronal dynamics.
In this paper, complex dynamical synchronization in a non-linear model of a neural system is studied, and the computational significance of the behaviours is explored. The local neural dynamics is determined by voltage- and ligand-gated ion channels and feedback between densely interconnected excitatory and inhibitory neurons. A mesoscopic array of local networks is modelled by introducing coupling between the local networks via weak 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 associated with complex, intermittent behaviour in the temporal domain and clusters of synchronous regions in the spatial domain. The paper concludes with a discussion of the putative relevance of such processes in the brain, including the role of neuromodulatory systems and the mechanisms underlying sensory perception, adaptation, computation and complexity.
Breakspear
Michael
M
Brain Dynamics Centre, Westmead Hospital, Westmead, NSW 2145, Australia. mbreak@physics.usyd.edu.au
Terry
John R
JR
Friston
Karl J
KJ
D000200:Action Potentials; D000818:Animals; D003198:Computer Simulation; D003344:Cortical Synchronization; D019706:Excitatory Postsynaptic Potentials; D005246:Feedback; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology*; D008564:Membrane Potentials; D008959:Models, Neurological; D009433:Neural Inhibition; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D013569:Synapses / Q000502:physiology*; D013997:Time Factors