MAPT and Alzheimer disease: In our recent studies, we observed that constant illumination could induce tau hyperphosphorylation, memory deficits and imbalance of kinases/phosphatases with ER damage.48 Rats brain treated with TM, an ER stress inducer, could significantly increase the phosphorylated tau.9, 38 These studies indicate a crucial role of ER stress in the AD‐like tau pathology and behavioural abnormalities.