Tau phosphorylation in mice has been demonstrated to follow a circadian rhythm that depends on body temperature, with tau being hyperphosphorylated during sleep.93 In a transgenic mouse model of Alzheimer’s disease, irregular sleep–wake cycles induced by sleep deprivation resulted in dysfunctional tau metabolism.94 One study identified a mechanistic link between altered circadian function and tau aggravation. This evidence concerns the gene MAPT and Alzheimer disease.