Fig. 1.

(a) Schematic of the reward discrimination task and block structure. For details about the task see ‘Materials and Methods’ section. (b) Choice curves for left target choice from a single session; reward for left target increases along x-axis; top: monkey M1, bottom: monkey M2. In both monkeys choice for left target reliably increased with increasing reward size, but the choice curves for cue-left (red) and cue-right (blue) trials were shifted from each other along the x-axis. (c) Mean ± SEM PSEs for cue-left and cue-right trials, pooled data from two monkeys. (d) Single-session and mean ± SEM ΔPSE values from two monkeys. (e) Normalized saccade RT showing interaction of reward congruency and cue congruency. Cue-congruent saccades were faster than cue-incongruent ones, but only when made toward the low-reward targets.