Figure 1.

Exploration and habituation to an OF. McGill-R-Thy1-APP Tg+/– male rats (dark gray bars) and their wt littermates (white bars) were trained and tested for short-term (ST, intra-session) habituation to an OF at (A) 3, (B) 4, and (C) 6-months of age. Bar diagram shows median and interquartile ranges (25;75) for the number of crossings recorded during each minute of a 5 min session (training, Tr). Significant differences were assessed by Wilcoxon matched pairs signed rank test; *P < 0.05, **P < 0.01, ***P < 0.001 (3 mo: N_wt = 8, N_Tg+/− = 11; 4 mo: N_wt = 8, N_Tg+/− = 11; 6 mo: N_wt = 11, N_Tg+/− = 10). (D) Long-term (LT) habituation to an OF (LTM). Bar diagram shows median and interquartile ranges (25;75) for the total number of crossings recorded during a 5 min training session (Tr, plain bars) and during the test session (Te, stripped bars) which was performed 24 h later (schematic representation of the task steps on top). No significant differences were observed between any selected pair of training sessions amongst the wt or Tg+/– animals (Unmatched Kruskal-Wallis test with Dunn's multiple comparisons). Total crossings during test session were significantly lower than during training session for the three different ages, either for wt or Tg animals. Statistically significant differences were assessed by Wilcoxon matched pairs signed rank test; *P < 0.05, **P < 0.01 (3 mo: N_wt = 8, N_Tg+/− = 8; 4 mo: N_wt = 8, N_Tg+/− = 9; 6 mo: N_wt = 11, N_Tg+/− = 8).