Effect of repetitive coupling of both leftward and rightward saccades with SC stimulation. In this experiment, stimulation was applied to the left SC. a, Course of saccade endpoint shift. b, Two dimensional distribution of saccade endpoints before (blue) and after (red) the stimulation session. Same format as in Figure 4b. Rt, Rightward; Lt, leftward; Dir, direction; Amp, amplitude; “deg” denotes saccade direction.