Seizure interactions between the inferior collicular cortex and the deep prepiriform cortex

Abstract

In rats, electrographic seizure activity was recorded from both the inferior collicular cortex and the deep prepiriform after i.p. administration of 15 μmol/kg bicuculline, a dose which produced a variety of seizure behaviors. Electrographic spikes recorded from the deep prepiriform cortex coincided with myoclonic jerks, while both brain areas exhibited an increase in afterdischarge frequency at the onset of forelimb tonic extension. Conversely, afterdischarge activity was recorded in both brain regions, while no seizure behaviors were apparent, providing examples of dissociation between electrographic and behavioral seizure activity. However, when functional interactions were assessed, the tonic-clonic behaviors produced by kindling stimulation of the inferior collicular cortex were prevented by microinjections of procaine into the deep prepiriform cortex. Thus, a forebrain site, that has been associated with limbic seizure activity, also can modulate seizure generalization from the inferior collicular cortex into the forebrain.