MAPT and Mental deterioration: Since accumulations of insoluble deposits of proteins β-Amyloid (Aβ) and hyper-phosphorylated (p)-Tau are the characteristic pathology features of cognitive decline in dementia patients, we determined whether deficiency of Jak3 expression led cognitive impairments were associated with Aβ and pTau accumulation under a normal diet (ND) and whether a high-fat diet (HFD) influenced such accumulation.