An epileptic seizure is a paroxysmally occurring functional disturbance of the CNS. Prior to electrophysiological investigations Jackson (1870) suggested: “An epileptic seizure is a state produced by an abnormal excessive neuronal discharge within the central nervous system.” More than 100 years of clinical and experimental investigations in the field of epileptology support and confirm this speculative consideration. The huge amount of experimental data has been made possible by the existence of a large variety of different animal models with focal and generalized epilepsy. Based on these data this brief review will mainly take into account experience from investigations dealing with focal epilepsy. To be within the scope of this volume, special emphasis will be put on the cellular mechanisms during epileptic activity, forming the first section. A second part describes the processes initiating and suppressing the outburst of a seizure. Finally an attempt will be made to elucidate the phenomena terminating a seizure. Other aspects, especially the generation of field potentials during epileptic activity and the mechanisms initiating the kindling process, will be described by Speckmann and Walden (this volume). Furthermore, a number of recent reviews cover other aspects of the basic epileptology in more detail (Conners and Gutnick 1984; Prince 1985).
KeywordsCortical Surface Focal Epilepsy Epileptic Activity Epileptic Focus Membrane Potential Change
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