Cortical kindling in a focal freeze lesion rat model

Focal cortical dysplasia (FCD) is of increasing interest as a cause of focal epilepsy. We aimed to determine whether the existence of FCD influences the epileptogenicity induced by electrical kindling stimulation of the cortices. We created an FCD rat model by focal contact of a frozen metal probe on the scalp immediately after birth. To produce afterdischarges (ADs), electrical stimulation was applied to the frontal cortices once daily for 20 consecutive days from postnatal day 38 (P38). Thresholds and durations of ADs were measured. Brains were exposed and examined histologically at P58. We observed mild FCD, which consisted of disorganized cortices with extra sulci; however, there was no statistical difference in the thresholds or durations of ADs between FCD rats and control animals. These results suggest that FCD might not influence vulnerability to epileptogenicity, at least in some patients with mild FCD.