The origins of Alzheimer's remain contentious, but a new study suggests the disease may emerge as two key proteins compete inside brain cells. Alzheimer's disease, the most common form of dementia, has long been associated with the build-up of two proteins in the brain: amyloid-beta and tau. This new study ties those two together, offering a " unifying theory " that, according to the team of chemists proposing it, resolves some conflicting ideas about Alzheimer's. Amyloid-beta peptides are