Spontaneous Electrographic Seizures in the Hippocampal Slice: An In Vitro Model for the Study of the Transition from Interictal Bursting to Ictal Activity

Abstract

Recently, several methods of provoking robust seizure discharges in the hippocampal slice preparation have been reported from our laboratory and from others. These seizure discharges are of long duration, complex morphology and have a stereotyped temporal evolution. Therefore, they are clearly different from the interictal bursts previously studied in the slice preparation. They resemble the seizures recorded from the intact brains of animals and humans, as for example, when recording from hippocampal depth electrodes in patients being considered for epilepsy surgery. Because of these similarities, we refer to these events as electrographic seizures or EGSs. Our hope is that the mechanisms of the EGSs in the slice are similar to the mechanisms of actual ictal events in the intact brain. If this is the case, the simpler slice preparation can be used to help us understand the transition from interictal activity to seizures as it occurs in the whole brain.