Figure 5.

Quantitative analysis of the effect of reward size on the initiation of pursuit for single targets in two monkeys. A, B, Time course of the difference in the eye velocity during the initiation of pursuit between trials that led to large versus small rewards. Different colors indicate different directions of target motion, solid curves are the averages, and the lighter shading shows the SEM across experiments. Positive values indicate that eye velocity was larger in trials that led to large rewards. C, D, Scatter plots comparing the average velocity 200 ms after the onset of target motion for trials that led to small versus large rewards. Each point shows data for a single experimental day. Different colors correspond to the colors used to indicate different directions of target motion in A and B. The oblique dashed line indicates equal eye velocity for large versus small rewards; points that lie below the line indicate that eye velocity was smaller in trials that delivered smaller rewards. The number of sessions was 15 for monkey P in each direction and 16 and 17 sessions for the vertical and horizontal directions for monkey I.