MAPT and Alzheimer disease: For instance, in AD tau pathology first appears in the transentorhinal cortex in the medial temporal lobe (Braak stages I/II, or preclinical AD), then it progresses to limbic regions (Braak stages III/IV, or prodromal AD) and finally to the neocortex (Braak stages V/VI, or clinical AD; Braak and Braak, 1995).