Abstracts

Functional alterations in neural networks are thought to underlie both susceptibility to seizures and interictal behaviours. Our laboratory has previously shown that electrical kindling of the rat neocortex, amygdala or hippocampus results in a dramatic expansion of motor maps. The aim of the current study was to determine if those observations extend to another model of epilepsy. In this study we employed the pilocarpine-induced status epilepticus model that results in extended seizure activity and, after a maturation interval, can ultimately lead to spontaneous seizures., Young adult male rats were injected with atropine methyl-nitrate (10.0 mg/kg) 30 minutes prior to convulsant treatment in order to block peripheral affects. Pilocarpine (320.0 mg/kg) was administered intraperitoneally at a dose that elicited seizures in all rats with approximately 50% expressing status epilepticus. Control rats received physiological saline. All rats were videotaped for 2 hours following convulsant administration or control. Seizure behaviours were quantified by duration and type. Diazepam (10.0 mg/kg) was administered to all rats 1.5 hours following convulsant or control injections to terminate seizure activity and promote survival. Rats had high-resolution intracortical microstimulation movement representations derived using standard methodologies at either 48 hours, 1 week, 2 weeks or 3 weeks following treatment., Our preliminary results show that rats have motor map expansion following pilocarpine treatment, regardless of whether status epilepticus occurred or not., These results demonstrate that a single episode of seizure activity induced by a convulsant agent can alter the functional expression of motor maps., (Supported by Natural Sciences and Engineering Research Council of Canada.)