APP and Alzheimer disease: Recent reports demonstrate deficient nesting behavior across different lines of APP-overexpressing transgenic mice such as Tg2576,34, 45 APPswe/PS146, 47 and 3xTg-AD.48 We found that nest construction behavior was significantly impaired in 5XFAD mice at 6, 9 and 12 months of age (P<0.05) but not at 4 months of age, as compared with that of the respective age-matched wild-type controls (Figure 1c).