![]() ![]() We argue that a delicately balanced interplay between Hopf and Turing modes provides a canonical mechanism for the default non-cognitive rest state of the brain. The model dynamics exhibits both Hopf (temporal) and Turing (spatial) instabilities the Hopf instability corresponds to the slow ([≲8 Hz) oscillatory states similar to those seen in slow-wave sleep, general anesthesia, and seizures. ![]() ![]() Here we report theoretical predictions for a physiologically-based cortical model that describes the general anesthetic phase transition from consciousness to coma, and includes both chemical synaptic and direct electrotonic synapses. Since gap junctions provide a direct electrical connection between adjoining neurons, thus enhancing synchronous behavior, reducing gap-junction conductance should suppress seizures however there is no clear experimental evidence for this. A generalized seizure event is a pathological brain state that is the clearest manifestation of waves of synchronized neuronal activity. Therefore the oscillatory state might be an indication of failure to form coherent neuronal assemblies necessary for consciousness. These states are characterized by low-frequency large-amplitude traveling waves in scalp electroencephalogram. During slow-wave sleep, general anesthesia, and generalized seizures, there is an absence of consciousness. ![]()
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