The vascular changes in the hippocampus and neocortex during kainic acid-induced seizures were investigated in control rats and in rats with chronic, bilateral, cervical sympathectomy. Seizures were induced in unanesthetized, spontaneously breathing rats. The increase in blood flow in the hippocampus of the sympathectomized rats was significantly reduced during the motor seizures, while the reduction in the neocortex was only significant when the increased blood flow was maximal.