Developmental Changes in Peak-Wave Discharges in WAG/Rij Rats with Genetic Absence Epilepsy

WAG-Rij rats are a model of genetic absence epilepsy, characterized by the presence of peak-wave discharges (PWD) on the EEG. The first PWD in WAG-Rij rats are known to occur at age 2–3 months, the number and duration then increasing. However, the evolution of PWD during the progressive development of absence epilepsy in WAG-Rij rats remains uninvestigated. The aim of the present work was to identify developmental changes in the time-frequency dynamics, frequency spectrum, and morphological features of PWD in WAG-Rij rats. The evolution of PWD was studied in individual rats from age two months to age 12 months. PWD were found to form at age 2–4 months, after which morphological changes in PWD were seen. During the progressive development of absence epilepsy, PWD displayed three stages of “maturation.” It is suggested that the age-related evolution of PWD in rats may reflect progressive electrophysiological changes in the somatosensory cortex – a brain area linked with the generation and generalization of PWD.