NTRK2 and memory impairment: Therefore, 5XFAD mice showed age-dependent deficits in nest-building performance with the onset of 6 months, which was similar to that of hippocampus-dependent memory impairments in this AD model.38, 39, 40, 41 Nevertheless, nest building was not affected in TrkB+/–·5XFAD mice at 4–5 months of age (Figure 1d), suggesting that TrkB haploinsufficiency specifically aggravated hippocampal memory dysfunction without affecting the impairment of nesting behavior in 5XFAD mice.