MAPT and Alzheimer disease: However, under disease conditions, Tau can become abnormally phosphorylated, leading to detachment from microtubules and the formation of Tau oligomer (oTau) and fibrils within the somatodendritic compartment.57 This process of Tau oligomerization is believed to be a critical factor for initiating neuronal loss and cognitive impairment observed in neurodegenerative disorders.58 We prepared oTau from postmortem brain tissues of patients with AD (Figures S5A and S5B) and introduced them into N-MG co-cultures to serve as a source of the pathological Tau.