Epileptic Seizure Dynamics as a Selforganised Spatio-temporal Pattern
Since their original conception as manifestations of electric brain activity by Hughlings Jackson, epileptic seizures have been considered an example of a pathology that is best described by a complex spatio-temporal pattern. Nevertheless, their understanding in terms of nonlinear dynamics is still surprisingly limited. In particular, the transition into and out of seizure dynamics is widely regarded to be due to specific parameter changes into and out of a region of periodic solutions, although these changes have never been pinned down to actual physiological observables.
Here we present a modelling framework for spatio-temporal epileptic dynamics in humans which builds on the notion of neural mass excitability of a generic cortical circuit. We justify the components of the model by comparison to experimental (animal) and clinical (human) data and study potential mechanisms underlying generalised and partial seizures. We find that, in addition to the dynamics provided by periodic attractors, spatio-temporal epileptic rhythms could also be explained by intermittency (spontaneous switching), and complex rhythmic transients following perturbations. We discuss these concepts using different clinical seizure types. Finally, we use the model framework to propose practical stimulation protocols to test for the presence of regions of abnormality ("epileptic foci") in the human brain.
M. Goodfellow, K. Schindler, G. Baier, NeuroImage 55, 920-932 (2011); M. Goodfellow, K. Schindler, G. Baier, NeuroImage (2011), doi:10.1016/j.neuroimage.2011.08.060. P. Taylor, G. Baier, J. Comput. Neurosci. (2011), in print. Online: DOI 10.1007/s10827-011-0332-1.