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. 2018 Jun 13;7:e35988. doi: 10.7554/eLife.35988

Figure 1. Positive incentive learning in mice.

(A) Schematic showing training, re-exposure and testing schedule for positive incentive learning. Group n’s: 2→ 2: n = 5; 2→ 16: n = 11. Data points and bar graphs represent the mean ± SEM. (B) Number of licks and (C) licking rate (10 min bins) during the re-exposure session. (D) The average latency to begin licking after a sucrose delivery (s). (E) The ratio of licks that occur in bursts, (F) average duration of bursts (ms), (G) average number of licks within a burst, and (H) average interlick interval within bursts (ms). (I) Average burst duration after a sucrose delivery and (J) average number of licks within a burst after a sucrose delivery. (K) Response rate during the 5 min non-rewarded test as a percent of acquisition response rate (last 2 days of training). (L) Schematic of training, re-exposure, and testing schedule for context positive incentive learning. Group n’s: context + sucrose -: n = 5; context + sucrose + : n = 11; context - sucrose -: n = 11; context – sucrose +: n = 11 (M). (J) Percent of baseline responding (last two training days) for mice not exposed to sucrose, not exposed to sucrose nor the context, exposed to sucrose in the context, and exposed to sucrose in the home cage. * indicates p=0.05, # indicates p=0.06.

Figure 1.

Figure 1—figure supplement 1. Acquisition of lever pressing for positive and context incentive learning.

Figure 1—figure supplement 1.

(A) Responses per minute during training days on the left lever for positive incentive learning group. Two-way repeated measured ANOVA: no interaction; no effect of group; main effect of training day (F (7, 70)=3.375, p=0.0037). (B) Left lever presses for each training day for incentive learning. Two-way repeated measures ANOVA: no interaction; no effect of group; main effect of training day: F (7,70)=3.37, p=0.0037. (C) Sucrose outcomes earned each training day during positive incentive learning. Two-way repeated measures ANOVA: no interaction; no effect of group; main effect of training day: F(10,100) = 2.58, p=0.008. (D) For context experiment, mice were trained at a 2 hr food restriction and tested at a 16 hr restriction. Mice were either re-exposed to sucrose in the operant context, in their home cage, or were not re-exposed to sucrose and had the same amount of time in the operant context or home cage. Responses per minute of mice trained at a 2 hr restriction. Two-way repeated measures ANOVA: No interaction or main effects (Fs < 1.52, ps >.19) (E) Left lever presses over each training day. Two-way repeated measures ANOVA: no interaction: F = 1.02, p=0.44; no main effect of Group: F = 0.90, p=0.46; main effect of training day: F(5,130) = 2.82, p=0.0187. (F) Sucrose outcomes earned over training days. Two-way repeated measures ANOVA: no Group x training day interaction, F = 0.90, p=0.61; no main effect of group, F = 2.38, p=0.09; main effect of training day: F(8,232) = 9.72, p<0.0001. (G) Left lever presses on non-rewarded test day for positive incentive learning. Unpaired t-test: F < 1.01, p>0.99.