Coefficients (means ± SEM across animals) of model parameters are shown for models 1–6 (see Materials and methods). In all models, CNO significantly increased randomness in action selection in D1R-Cre mice and significantly decreased learning rate in D2R-Cre mice. Left, D1R-Cre mice; right, D2R-Cre mice. α, learning rate; αpos, learning rate for positive outcome (rewarded trials); αneg, learning rate for negative outcome (unrewarded trials); β, randomness in action selection; VL, choice bias; WS, win-stay; LS, lose-switch; ε and ρ, parameters for uncertainty-based exploration (see Materials and methods). P-values are indicated for those measures with significant main effects of drug and/or mouse line × drug interaction (Intx) effects (two-way mixed-design ANOVA). Asterisks indicate the results of Bonferroni post-hoc tests (*p<0.05; **p<0.01; ***p<0.001).