Reversal learning deficit in Dlgap2−/−mice. The water T-maze test was performed as described in Methods. (A) Days needed to reach criteria for reversal learning in the habit acquisition session. (B) Percentage of correct trials without errors throughout the 6-day habit acquisition session. Note that there was no difference between WT and Dlgap2−/−KO mice in the acquisition phase. (C) Total number of errors made on Day 1 of reversal learning session. Note that more errors were made by Dlgap2 KO mice on the first day of reversal learning. (D) Total numbers of errors made during the 4-day reversal learning session. Data are presented as mean ± standard error. n = 5 for each group. * P < 0.05 compared with WT. KO, knockout; WT, wild type.