MAPT and Alzheimer disease: Consistent with inclusion of MBI in the National Institute on Aging Alzheimer's Association (NIA-AA) criteria for diagnosing and staging AD,8 our findings show that MBI-apathy is associated with established core 1 (Aβ proteinopathy, p-tau and secreted AD tau) and core 2 (AD tau proteinopathy) biomarkers, which reflect neuritic plaque and tau accumulation that are indicative of early- and later-stage AD pathology.