Mouse models of AD show behavioral deficits on a variety of tasks that model aspects of the human disease including passive avoidance, fear conditioning, and various mazes (Webster et al., 2014). Since these and other commonly used tasks require motor function, interpretation of altered performance can be complicated by the presence of motor deficits. Evidence indicates that 3xTg-AD show reduced locomotor activity in the open field at 12–18 months of age (Filali et al., 2012; Gulinello et al., 2009). By contrast, 3xTg-AD mice at both 6 months (Stover, Campbell, Van Winssen, & Brown, 2015b) and 16 months (Garvock-de Montbrun, Fertan, Stover, & Brown, 2019) of age show improved performance as compared to WT controls on the rotarod test suggesting improved motor coordination. Importantly, however, 16-month-old 3xTg-AD mice show an age-dependent deficit in performance on rotarod, grip strength, gait analysis and balance beam tests as compared to younger 6-month-old 3xTg-AD mice (Garvock-de Montbrun et al., 2019). Overall, these findings underscore the importance of evaluating performance of 3xTg-AD mice on AD-related cognitive tasks in the context of potential motor abnormalities.
