Figure 1
Schematic illustration of the home-cage training system and tasks. (a) Home-cage training system. The photograph on the left shows the cage interface (CI) connected through the guillotine door to the experimental cage. The monkey sits in front of the opening of the CI (1) where a stainless steel tube (2) releases the reward via a reward system (top right image). A touchscreen (3) allows the monkey to perform the task. A wide-angle camera (4) monitors the monkey during sessions. The lower image shows the behavioral control unit, which is connected to the touchscreen, reward system, and camera and is used to run the tasks and record the monkey’s responses. (b) The 19 steps presented during phase 1 of experiment 1. The monkey learns to touch a central stimulus (CS) of progressively smaller size (steps 1–5); to keep touching the CS while it is on the screen (steps 6–11); to remove its hand after the CS is turned off within a specific time window (steps 12–15), and to touch and continue toughing a target when it is presented on the screen (steps 16–19). (c) The sequence of events of one trial of the non-match-to-goal task. The upper section shows a trial performed by the monkeys in phase 2 of experiment 1 and in experiment 2. The lower section shows a trial performed by the ghost agent in experiment 2. The black rectangle represents the touchscreen. The white or red circle is the CS, and the disappearance of the CS represents the go signal for starting the movement. The targets (here, a pink rhombus and a yellow cross) are the stimuli for the choice. The gray rectangle in the computer trial simulates the sequence of actions necessary to carry out a correct complete trial. The first black rectangle on the left shows the target chosen in the previous trial that was, according to the task design, presented again in the current trial, alongside a different stimulus. On the right the four targets and the four types of visual feedback for both experiments are shown. Under the two example trials, the duration of each is shown.
