Fig. 1.

Experimental paradigms. A: experimental protocol for recording head-fixed saccades. Gray and black circles denote gaze and target position, respectively. Dashed box denotes space of possible target placements. B: experimental protocol for recording head-unrestrained reaching. Subjects were seated in a custom-built chair with shoulder-fitted seat belts. Eye tracker was placed above the viewing screen with use of a hot mirror to enable simultaneous recording of hand movements. Subjects were asked to make reaching movements and gaze shifts to a series of circular targets (diameter = 1.0°) in the upper horizontal quadrant of the viewing screen.