MAPT and Alzheimer disease: As expected, though, atrophy rates significantly increased in subjects more advanced in the disease stage, when both Aβ and tau were positive.9 Altogether, these results support an inverted U-shape for structural changes in Alzheimer’s disease, as previously suggested,8,9,24 with a slight GM thickening in early stages, mainly related to Aβ positivity, that will be followed by a pathology-related atrophy process when subjects become tau-positive.