Fig. 2.

Acquisition of visible and hidden platform locations in Tg5469 and Tg2576 mice. a, Escape latencies of Tg5469 and Tg2576 mice in the visible platform version of the Morris water maze (2 blocks of 4 trials each day). No significant effect of transgene was found in the last two training blocks for either line of mouse at any age, mitigating against sensorimotor deficits as a potential explanation for impaired performance in acquisition or retention of the location of the hidden platform. Although middle-aged and old Tg2576 Tg+ mice showed an initial lag in performance, their performance was not significantly different from Tg− mice on the final day. b, Escape latencies of Tg5469 and Tg2576 mice swimming to the hidden platform in the Morris water maze. A significant age-by-transgene interaction for mean escape times during the last three training blocks was seen in Tg2576 mice (ANOVA;p < 0.005). Post hoc analysis showed significant effects of transgene in middle-aged and old Tg2576 mice (t test; **p < 0.0001).