Febrile seizures in the predisposed brain: a new model of temporal lobe epilepsy.

The atypical febrile seizure has important clinical implications because of its association with the mesial temporal lobe epilepsy syndrome, which is the most common of the intractable epilepsies. However, whether a causal relation exists between these conditions is currently unknown. We have previously shown that a focal cortical lesion induced in the neonatal rat predisposes to the development of atypical hyperthermic seizures. We show here that 86% of the lesion plus hyperthermia group experience development of spontaneous recurrent seizures recorded from the amygdala ipsilateral to the lesion. Control rats did not have spontaneous recurrent behavioral or electrographic seizures. Lesioned rats with hyperthermic seizures also showed an impaired performance on the Morris water maze when compared with naive control rats, suggesting mild deficits in learning and memory. These findings support a link between the atypical febrile seizure and mesial temporal lobe epilepsy, and at the same time establish a new model for this condition through which new preventative and therapeutic strategies can be tested.