Figure 3. Dlx5/6^+/− mice are not impaired in rule reversals.

(A) Schematic illustrating how we assayed rule reversals either before or after rule shifts. In all cases, mice first learn an initial association between the food reward and one stimulus, e.g., odor 1 (O1). In some cases (black arrows), the mice then experience a rule shift (RS) in which a previously irrelevant stimulus, e.g., texture A (TA), becomes associated with reward. In the other cases (blue arrows), immediately following the initial association, mice learn a rule reversal (RR), in which the stimulus that was unrewarded during the initial association, e.g., odor 2 (O2), now becomes associated with reward. In both cases, all three portions of the task (IA / RS / RR or IA / RR / RS) were completed consecutively on one day. The rule reversal always tested the ability of mice to learn a reversal of the association that they had successfully acquired during the IA, whereas the rule shift always tested mice on their ability to learn a rule based a stimulus that was previously irrelevant to the outcome of each trial.

(B) Performance of adult Dlx5/6^+/− mice and their wild-type littermates in the IA, followed by the RS, and RR.

(C) Performance of adult Dlx5/6^+/− mice in the IA, followed by the RR, and RS.

(D) During the rule shift shown in (C), adult Dlx5/6^+/− mice made a preponderance of perseverative errors, compared to random errors.

All data show means ± SEM and are analyzed using two-tailed Student's t-tests. **p < 0.01, ***p < 0.001.