Simulated neural activity, movement time and approach direction of reaching trajectories, in free-choice and cued-reaching trials in an effector choice task.

<p><b>A</b>: Time course of the average activity (20 trials) of the two populations of neurons tuned to the selected (solid black line) and the non-selected (discontinuous black line) targets prior to movement onset, from the DNFs that plan reaching (green color) and saccade (red color) movements in the “free-choice” sessions. Data shown only when reaches were selected. Notice that the framework selects first which effector to use to perform the task and then it chooses the target. The average activity from the saccade DNF for the selected and non-selected targets overlaps. <b>B</b>: Similar to panel A, but for the “cued-reaching” sessions. The competition between the effectors is resolved almost immediately after the cue onset. <b>C</b>: Mean movement (i.e., response) time from 20 reaching trajectories in a free-choice task (i.e., model is free to choose to perform hand or eye movement to acquire each of the targets) and a cued task, in which the model was instructed to perform reaches. The error bars are ± standard error. The movement time in the free-choice trials was significantly lower than the movement time in the cued-reaching trials (two-sample <i>t</i>-test, <i>p</i> < 10⁻⁷). <b>D</b>: Mean approach direction of 20 reaching movements for the first 50 time-steps in a free-choice task and a cued-reaching task. The error bars are ± standard error. Approach direction at 0 deg. indicates that initial reaching movements were made towards the intermediate location between the two targets. Notice that free-choice trials are characterized with straight reaching movements to the selected target, whereas the cued-reaching trials are dominated mostly by curved reaching movements to the selected target (two-sample <i>t</i>-test, <i>p</i> < 10⁻⁴).