Figure 2. Conditional Discrimination and Inhibition Task Used in Both Rodents and Humans.

Note. (A) A fear-reward-inhibitor cue discrimination task developed in rats and modified for use in humans. In both versions, different environmental cues, either auditory or visual, are conditioned to represent (a) fear by pairing it with either footshock (rats) or an aversive auditory stimulus (humans), (b) reward by pairing it with either sucrose (rats) or money (humans), or (c) an inhibitor by presenting it alone without any outcome. Trials where compound presentations of the (d) fear + inhibitor and (e) reward + inhibitor without any outcomes are also included. (B, C) Schematic representation of data is reported in (Greiner et al., 2019) and (Krueger et al., 2024). At the end of discriminative conditioning, most male rats show higher freezing compared to all other cues, while most female rats do not show appreciable reductions in freezing to the fear + inhibitor cue. Both male and female rats show higher reward seeking to the reward cue compared to all other cues. (D, E) Schematic representation of data is reported in (Fitzgerald et al., 2023). Skin conductance responses in healthy adults were higher to the fear and reward cues compared to all other cues, indicating higher arousal to these cues compared to the FI, I, and RI trials. Self-reported likeability ratings from the same subjects showed the reward cue was rated most favorably and the fear cue least favorably, with the FI, I, and RI cues rated in the neutral range. See the online article for the color version of this figure.