APP and Anxiety: Although anxiety levels were not measured in this study, other studies have found that Tg animals tend to have higher levels of anxiety [18, 24, 25, 26] and thus, it is possible that APP21 and APP+PS1 rats continue to be motivated to escape the aversive nature of the Barnes maze even after many training trials, whereas the WT animals may learn that the maze environment is no longer fear-inducing after being exposed to it over many trials.