Propagation Dynamics of Epileptiform Activity Acutely Induced by Bicuculline in the Hippocampal–Parahippocampal Region of the Isolated Guinea Pig Brain

Abstract

Several studies proposed that reciprocal connections between the entorhinal and the PRC are under a very efficient inhibitory control (1). We report that ISs determined by acute bicuculline treatment in the isolated guinea pig brain progress from the PC to the hippocampus/EC just before ictal onset. Ictal discharges are characterized by a peculiar pattern of fast activity that originates from the entorhinal/hippocampal region and only secondarily propagates to the PRC. Postictal propagation of ISs to the PRC occurred exclusively when an ictal discharge was generated in the hippocampal/entorhinal region. The results suggest that reiteration of ictal events may promote changes in propagation pattern of epileptiform discharges that could act as trigger elements in the development of temporal lobe epilepsy.