Cued learning. Learning performances in 16 trials of 2 min were assessed as latency to reach the beacon platform in the Morris water maze and are represented in 4 blocks of 4 trials. Linear regression curve of learning pattern for WT: y = -12.23 x + 86 and for KO: y = -15 x + 93 for KO. * at least P < 0.05 vs. each other trial for WT; ^^ at least P < 0.01 vs. each other trial for KO, Bonferroni post hoc. WT n = 7-10, KO n = 7-11.