Critical evaluation of animal models for localization-related epilepsies.

There are many forms of human partial seizures and many human localization-related epilepsies. Idiopathic epilepsies undoubtedly have pathophysiologic substrates different from those of symptomatic epilepsies, and there is evidence that some forms of limbic epilepsy involve different epileptogenic mechanisms than neocortical epilepsies. Although these mechanisms are best studied and understood by direct investigations of patients, this is often impractical and experimental animal models are also necessary. The use of experimental animals requires that the relevance of each model to a human condition be determined. Human epilepsies are comprised of multiple component parts which can be modeled independently. For instance, acute animal models provide opportunities to study epileptic seizures, but chronic models are necessary for investigation of processes relevant to epileptic conditions, such as epileptogenesis, transition from interictal to ictal state, and long-term consequences of epilepsy. Interactions between localized epileptic activity and cerebral maturation can also be studied in the animal laboratory. Experimental animal models of human partial seizures and localization-related epilepsies can be used to further investigations on basic mechanisms that cannot be pursued in patients, and to develop hypotheses concerning the fundamental neuronal processes underlying epilepsy and epilepsy-related phenomena that subsequently can be validated in patients. In addition, it would be of great clinical utility to develop animal models of partial seizures or localization-related epilepsy that could be used cost-effectively to screen potential anti-epileptic drugs.