MAPT and Alzheimer disease: In silico modeling is a powerful aid in structural-basedtracer design.32 Several in silico binding studies with different tracers have been reported for AD,CBD, and PSP tau protofibrils.33−37 Some interior tracer binding sites in the protofibrils (e.g., thee1 site in CBD tau) usually exhibit much stronger binding free energiesthan the fully exposed surface sites.35 However, the interior sites can be difficult to access in a realtissue with many long-range fibrils36 becausethe entrance to these sites of each real fibril may just interactwith the body of other fibrils.