Neurophysical modeling of brain dynamics

Abstract

A recent neurophysicalmodelof brain electricalactivity is outlined and applied to EEG phenomena. It incorporates single-neuron physiology and the large-scale anatomy of corticocorticaland corticothalamic pathways, including synaptic strengths, dendritic propagation, nonlinear firing responses, and axonalconduction. Smallperturbations from steady states account for observed EEGs as functions of arousal. Evoked response potentials (ERPs), correlation, and coherence functions are also reproduced. Feedback via thalamic nucleiis criticalin determining the forms of these quantities, the transition between sleep and waking, and stability against seizures. Many disorders correspond to significant changes in EEGs, which can potentially be quantified in terms ofthe underlying physiology usingthis theory. In the nonlinear regime, limit cycles are often seen, including a regime in which they have the characteristic petit mal3 Hz spike-and-wave form. © 2003 Nature Publishing Group.