Given the interconnectedness of brain processes leading to neurodegeneration (e.g., mitochondrial dysfunction, amyloid neurotoxicity, and tau neurotoxicity) and the fact that the onset of LOAD can be 20 or more years before the appearance of symptoms, it makes sense to apply pharmacotherapy to target multiple systems that regulate neurodegeneration, neuroplasticity, and brain neurochemistry in AD. Here, MAPT is linked to Alzheimer disease.