Fig. 3.

High-fat diet impairs learning in the smell recognition test in 3xTgAD and non-Tg mice. Male 3xTgAD and non-Tg control mice were maintained on either a control or high-fat diet from the age of 8 weeks. Cognitive function was assessed in the smell recognition test in separate groups of mice at the age of 3–4 (A), 7–8 (B), 11–12 (C), and 15–16 (D) months. During phase 1, the mice were placed in an arena for 10 minutes with 2 identically scented balls (data not shown). During phase 2, after an interval of 3 minutes, the mice were placed back into the arena with one familiar scented ball (presented in phase 1) and one novel scented ball for 4 minutes and percentage time exploring balls was compared. Data are means ± SEM. n = 6–12/group. * p < 0.05, ** p < 0.01 for novel versus familiar smell; Student t test. Abbreviation: SEM, standard error of the mean.