Improvement of memory guided saccades in parkinsonian patients by high frequency subthalamic nucleus stimulation

Recent studies in the monkey suggest that the subthalamic nucleus (STN) is involved in control of eye movement, yet its functional significance in hum ans is unknown. Saccadic eye movements were studied in eight parkinsonian p atients treated by bilateral electrical stimulation of the STN. STN stimula tion improved the accuracy of memory guided saccades but not of reflexive v isually guided saccades and had no effect on the antisaccade task. This stu dy shows that, by contrast with levodopa, STN stimulation improves memory g uided saccade deficits, and illustrates for the first time in humans the ro le of the STN in the control of purposive saccades.