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. 2019 Mar 6;39(10):1842–1854. doi: 10.1523/JNEUROSCI.3477-17.2018

Figure 2.

Figure 2.

Schematic diagram for the rGTs. The task began with illumination of the tray light. A nose-poke response in the food tray extinguished the tray light and initiated a new trial. After an ITI of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, and the animal was required to respond in one of these holes within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option (indicated by the probability of a win or loss in brackets for each option, hypothetical maximum number of pellets presented underneath each option). If the animal was rewarded, the stimulus lights were extinguished and the animal received the corresponding number of pellets in the now-illuminated food tray. Cued rGT animals also received concurrent win-paired audiovisual stimuli. The six tones used were as follows: 4, 8, 10, 12, 15, and 20 kHz. Using the letters A–F to represent a different tone, the patterns for P3 were as follows: CDEDCDEDCD; CECEDEDECE. Similarly, the patterns for P4 were as follows: ABCDEFEDCB; BCDCDEDEFE; CEDFCEBDAC; FEDCBAFEDC. With respect to the visual cues, the first light to flash was the hole associated with that response, shown here for version A. For P3 and P4, the visual stimuli then become more varied in the last second of the cue, using sequences of multiple lights that change in sync with the tones. Lights could illuminate together, as indicated by numbers in brackets, or independently. The patterns for P3 were as follows: 5434543454; (5 + 3)4 (5 + 3)4(5 + 3)4(5 + 3)4(5 + 3)4. The patterns for P4 were as follows: 1234543212; (2 + 4)(1 + 3 + 5)(2 + 4)(1 + 3 + 5)(2 + 4)(1 + 3 + 5)(2 + 4)(1 + 3 + 5)(2 + 4)(1 + 3 + 5); 1324354231; (2 + 4)(1 + 5)(2 + 4)3(2 + 4)(1 + 5)(2 + 4)3(2 + 4). Which tone/light pattern would play was determined randomly, but the same pattern was never presented on sequential P4 win trials. A response at the food tray then started a new trial. If the animal was punished, the stimulus light in the corresponding hole flashed at a frequency of 0.5 Hz for the duration of the punishing timeout and all other lights were extinguished. At the end of the punishment period, the tray light was turned on and the animal could initiate a new trial. Failure to respond at the illuminated holes resulted in an omission, whereas a response during the ITI was classified as a premature response and punished by a 5 s timeout during which the house light was turned on (schematic based upon Zeeb et al., 2009).