MAPT and Alzheimer disease: The studies usingcryo-EM structures for tau fibrils showed that the binding affinityof AV-1451 toward PiD tau fibrils was larger than that of the AD-taufibrils which was controversial with results from autoradiographystudies using brain homogenates.27,28 However, thecryptic sites found in AD-tau fibrils are found to be associated withhigh affinity for this tracer, and now the binding specificity forthis tracer toward AD-fibrils is correctly reproduced as observedin experiments.