Some studies also showed that defective autophagy is responsible foraccumulation of abnormal tau and amyloid.50,51 As neurons are non-proliferative,rejuvenation of aged neurons is a prerequisite for a functional brain inelderly.41, 42, 43 Many studies have shownthat repair of DNA damages and autophagic disposal of cellular wastes, for example,abnormal tau, are essential for neuronal rejuvenation.6, 7, 8,9, 10, 47 Failed repair of stressed neurons leads toneurodegeneration in the cortex and hippocampus after middle-age and subsequentAD-like dementia at old age. The gene discussed is MAPT; the disease is dementia.