MEMORY-GUIDED SACCADIC EYE-MOVEMENTS - EFFECTS OF CEREBELLAR DISEASE

We compared the accuracy of oblique, memory-guided saccades if the eye is stationary or moves horizontally during the memory period. We stud ied 11 patients with cerebellar disease and 11 age-marched control sub jects. Normal subjects showed similar accuracy of saccades for both co nditions. In contrast, all patients showed greater errors if the eye m oved horizontally during the memory period; however, errors of both ve rtical and horizontal components of memory-guided saccades were simila r. Thus, inaccuracy of memory-guided saccades could not be simply attr ibuted to failure to internally monitor change in horizontal gaze duri ng the memory period. Instead, we propose that the greater saccadic er rors which occurred when gaze changed during the memory period reflect ed a disruption of predictive mechanisms governing eye movements. (C) 1998 Elsevier Science Ltd. All rights reserved.