Figure 3

Cognitive behavior of APP/PS1 KI and wild-type control mice. Radial arm water maze (RAWM) performance for each age group: (A) no observable difference is seen between amyloid precursor protein/presenilin-1 knock-in (APP/PS1 KI) mice and wild-type (WT) mice at 7 months of age; however, cognitive deficits are observed in the APP/PS1 KI mice at (B) 11 months, (C) 15 months, and (D) 24 months. (E) RAWM performance as a function of total errors across the four age groups. The WT cognitive performance remained relatively constant across the age groups, while APP/PS1 KI cognitive performance became more impaired as age increased. Data are plotted as mean (solid line) and confidence intervals (dashed lines). (F) Novel object recognition (NOR) performance in APP/PS1 KI and WT mice. The D² recognition index is used to control for total exploration time: D² = (novel - familiar)/(novel + familiar). Beginning at 15 months of age, the APP/PS1 KI mice show an inability to discriminate between objects while the WT mice are still able to discriminate. (G) NOR performance as a function of D² recognition index across the four age groups. The WT cognitive performance remained relatively constant across the age groups, while APP/PS1 KI cognitive performance became more impaired as age increased. N = 5 to 10 mice per group. *P <0.05, for APP/PS1 KI compared with WT. Number of mice: 10 WT and nine KI mice aged 7 months; five WT and 12 KI mice aged 11 months; 10 WT and 10 KI mice aged 15 months; and seven WT and five KI mice aged 24 months.