Figure 1. Discriminative control by feeding condition in mice.

(A) Schematic of the operant hunger discrimination paradigm. During training sessions, responses on one designated active lever depending on feeding condition were reinforced (e.g., 22-h food-restricted, left lever active; 1-h food-restricted, right lever active) with sucrose pellets on an FR15 schedule, whereas responses on the opposite lever reset active lever requirements. During testing sessions, responses on both levers were reinforced. All sessions lasted for 20 min or until five pellets were earned.

(B) Group-averaged data for all mice (n = 35) on the first 25 sessions of each trial type. Condition-appropriate responding increased as training progressed.

(C) Mice qualified for training by performing >80% responses on the condition-appropriate lever (shown as dotted lines) for five consecutive sessions or six out of seven consecutive sessions. This graph shows training data from a representative mouse during training sessions 40 through 56. On sessions 51 through 56, the mouse exceeded the 80% threshold each session and qualified for testing.

(D) Acquisition curve depicting the number of sessions required for each mouse to reach training criteria. (n = 35 mice)

(E) Performance of mice during free-choice test sessions (n = 12 Agrp^Cre mice, 12 Vgat^Cre mice, and 11 Vglut2^Cre mice). Upper panels, condition-appropriate lever responding; lower panels, response rate.