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. The gene discussed is NTRK2; the disease is Alzheimer disease.