FIGURE 1.

The three phases of the pairwise discrimination operant task. Images in the pretraining phase were randomly selected from the manufacturer provided image repository. Yellow cylindrical icons indicate number of banana-flavored sucrose pellets dispensed. In Initial Touch, the clock icon indicates the outcome if the rat does not touch the image within 30 s. In Must Initiate and all subsequent phases, the rat icon indicates the added requirement of the rat starting each trial manually. In Punish Incorrect and subsequent phases, the X indicates a 5 s timeout. The opposite rewarded image used for the pairwise discrimination training (PD) phase was used for the reversal (REV) phase.