Ontogeny of the Epileptic System in the Krushinsky–Molodkina Rat Strain with Genetically Determined Audiogenic Epilepsy

Susceptibility to audiogenic epilepsy (AE) seizures and phenotypic manifestations of epileptic activity in rats of the Krushinsky-Molodkina (KM) strain were shown to develop in parallel with the appearance of seizure EEG patterns from 2 to 7 months of age. The seizure latency decreased with age, while the intensity of convulsive seizures increased. Two types of epileptiform discharges (EDs) were identified in background EEGs (no exposure to sound) of KM rats. One type had a form of high-amplitude generalized packs of waves with the animal shuddering. The other type had a form of generalized non-seizure absence-like spike-and-wave discharges with the animal freezing. The total and mean durations of single absence-like discharges increased with age. Parallel age-related increases in the severity of AE seizures and the number of generalized absence-like discharges in the forebrain EEG suggests the development of the epileptic system in KM rats.