Alzheimer's disease (AD) is the most common form of neurodegenerative disease and one of the leading causes of death in the Western world. The pathological changes in the brain due to AD include brain atrophy (progressive shrinkage of the brain) and enlargement of the lateral ventricle. From a histological perspective, the main change in the brain during AD is the progressive accumulation of beta-amyloid plaques and tau neurofibrillary tangles. Beta-amyloid proteins form irregular clumps in the brain, which combine to create plaques that disrupt the signals between synapses. These amyloid plaques initially develop in the neocortex and spread throughout the brain in the early phase of the disease.