Figure 1

(A) Memory-guided reaching task. The animals sat in an upright position in a primate chair at a distance approximately 30 cm from the screen. A 2-dimensional joystick was positioned in front of the sitting animals, with the handle at the level of their knees. A trial started with two central fixation cues, which the animals had to acquire with their eyes (red diamond) and with the joystick (green circle). Next, either a single green cue was presented in the left or the right hemifield (instructed trials) or two green cues were presented simultaneously in both hemifields (free-choice trials). The cues(s) disappeared after 380 ms; the animals had to remember their location during the delay period, and could select and plan the upcoming movement. After the green central fixation cue was extinguished (go signal), the animals had to make a reaching movement to the instructed or chosen target and wait there for another 300 ms to receive the reward. Importantly, the animals had to maintain eye fixation on the central red diamond cue throughout the reaching trial. (B) Memory-guided saccade task. It was similar to the reaching task described in A with the difference being that choices were made using eye movements (saccades). Red diamond cues indicate the location of the central fixation and the saccade targets.