Figure 2.

(A)Gpr88^Cre/Cre mice showed increased motivation compared with WT mice following reward devaluation with chow (t_45.89 = 5.607), milk (t_42.49 = 4.120), and free feeding (t_40.99 = 5.794). Main effect of devaluation, F_2.099,96.54 = 130.6, p < .0001; genotype, F_1,46 = 42.46, p < .0001; devaluation × genotype, F_3,138 = 3.39, p = .0199. (B) Consumption of chow and milk prior to testing did not significantly differ between Gpr88 knockout and WT mice. Repeated-measures two-way analysis of variance with Šídák’s multiple comparisons test; chow (t₉₂ = 0.06545; p = .997), milk (t₉₂ = 1.842; p = .133). N = 24 (WT males n = 12, females n = 12; Gpr88^Cre/Cre males n = 12, females n = 12). Individual data points presented with mean ± SEM. ∗∗∗p < .001, ∗∗∗∗p < .0001 determined by repeated-measures two-way analysis of variance with Geisser-Greenhouse correction and Šídák’s multiple comparisons test. FF, free feeding; PR, progressive ratio; WT, wild-type.