A disease propagation and progression model, composed of six stages of increasing pathological severity determined by the location of the tangle-bearing neurons and the amplitude of the pathophysiological changes.neocortical stages V-VI correspond to fully developed Alzheimer's disease. These stages are characterized by large numbers of NFTs in all sections of cerebral cortex and present neocortical damage thus contributing to the development of the conventional neuropathological criteria for the clinical diagnosis of AD.