ABSTRACT
The genetically epilepsy-prone rat (GEPR) provides a model of seizure predisposition, as well as a model of seizure expression. The animals are valuable because the presence of seizure predisposition is innately determined. The Audiogenic Response Severity (ARS) scale has been used extensively for evaluation of seizure mechanisms in the GEPR. It was introduced as a means of determining the severity of audiogenic seizures. Several lines of evidence support the idea that the ARS system represents seizures of increasing severity from the lowest to the highest score of the scale. Many convulsions arise from the forebrain. Facial and forelimb clonus, with or without rearing and falling, appears to emanate from the forebrain. A direct and linear relationship does not appear to exist between the seizure circuitries of the forebrain and the brainstem. Ontogenetic studies of convulsive expression in the GEPR appear to provide insight into the development of brainstem and forebrain seizure circuitries.
