Figure 4.

Enhancement of ocular following eye speed after real and simulated saccades and the effect of test direction. (A,B) Ocular following eye speed from one monkey for test stimuli presented after real saccades. In (A) the test stimuli were moving upward at 160°/s. Ocular following was robust for this test direction, and eye speed was significantly enhanced in the short-delay condition (blue) compared to the long-delay condition (gray). In (B) the test stimuli were moving downward at 160°/s. For this test direction ocular following was poor, with no evidence of post-saccadic enhancement. Ocular following was consistently poor for test stimuli moving in the downward direction. The remaining panels, (C–H), show ocular following eye speed for test stimuli moving at 160, 80, and 40°/s, averaged across all directions tested. Panels on the left [(C), 160°/s; (E), 80°/s; (G), 40°/s] show eye speed for test stimuli presented after real saccades. In all cases, ocular following eye speed was significantly enhanced in the short-delay condition (blue) compared to the long-delay condition (gray; ASL < 0.001). Panels on the right [(D), 160°/s; (F), 80°/s; (H), 40°/s] show corresponding ocular following eye speed for test stimuli presented after simulated saccades. Again, in each case ocular following eye speed was significantly enhanced in the short-delay condition (green) compared to the long-delay condition (gray; ASL < 0.001). In all panels, solid lines show eye speed signals averaged across all trials of a given speed and the shaded regions indicate ±1 SE, estimated by bootstrapping.