Figure 4: Morris water maze performed at 6-7-months of age using PS2Tg2576 mice. (a) The escape latency of the 6-7 month-old mice in the hidden platform trial. Training trials were repeated for 4 days (1 minute/trial, 4 trials/day). Only the PS2Tg2576 mice showed significant task errors on days 3 and 4 (using one-way ANOVA, * ). The graph shows representative swimming paths of individual mice on day 4 of the training phase. (b) The number of crossings of the removed-platform area during the probe test. A probe trial, in which the platform was removed, was performed for 2 minutes on the day after the training trials had finished. (c) Percentage of time spent in the target quadrant during the probe trial. (d) Representative swimming paths of individual mice during the training phase of the probe test. The arrowhead represents the entry point. Values represent the mean ± s.e.m. ( , approximately equal numbers of male and female mixture). Statistical significance was assessed using the unpaired -test (c, d): * compared with the wild-type mice at the same age.