Alzheimer's Disease is primarily caused by the deposition and accumulation of tau and amyloid protein within the neuronal networks in the brain. Generally, β-amyloid plaques first aggregate in the basal cortex before spreading to other brain structures. Significant tau neurofibrillary tangles have been found to first clump together in the transentorhinal area before spreading throughout the limbic area and in the association cortices. 

Deposition of these proteins induces gradual neuronal damage in individuals with AD, leading to AD’s clinical symptoms. Moreover, protein deposition impedes neuronal communication prior to cell death, which also leads to memory problems, difficulties in word finding, and the eventual, general cognitive decline and difficulty handling day-to-day tasks apparent in individuals suffering from AD.