Fig. 8
Behavioral tasks. During the recordings, rats performed one or two of the following tasks. (a) Risk-reward interaction task. Top, behavioral apparatus. LED panels behind the water ports and below the floor sectors served as CSs predicting liquid rewards (CS-Rs) and footshocks (CS-Ss), respectively. Bottom: trial types. Rats were presented with a random sequence of CS-Rs or CS-Ss. (b) Foraging task. The behavioral apparatus featured a dimly lit nest and a longer and brighter foraging arena where rats retrieved food pellets. On half the trial blocks, rats were confronted with a mechanical predator when they ventured in the foraging arena. (c) Operation task. Rats were presented with visual stimuli via two computer screens placed on either side of their heads. Rats had to determine on which side the target dimension was highest while ignoring the left-right difference in distractor levels. Rats reported their decision by pressing a lever on the side where the target dimension was higher. Depending on the trial, speed and brightness could be greater on the same side (“congruent trials”; d) or on opposite sides (“incongruent trials”; e). (f) Expectation control task. Hungry rats ran back and forth between the ends of an elongated arena to obtain food rewards. At each end of the arena was a food reward port and a nose-poking station. A third nose-poking station was placed in the middle of the arena. Rats were trained to nose-poke at one end of the arena and then at the arena’s midpoint, each nose-poke triggering the presentation of one of three tones (60 db; 0.7 s) that signaled how many food pellets could be retrieved at the arena’s other end.
