Fig. 4

How to differentiate the origin (PSP or AD) of each tau-positive lesion in comorbid brains with both PSP and AD pathology. Tau-positive lesions are sorted along regions indicated at the center column. Regions containing NFTs but not TAs are labeled in bold face (HF, IC: insular cortex, LC and PN). Other regions containing both NFTs and TAs are labeled in italics. Horizontal bars indicate relative quantity of TA and NFT in each region. IR to 4R tau (green) and that to 3R tau (red) are indicated by vertical lines. TAs are positive only for 4R tau as indicated on the left half. In contrast, NFTs were sometimes positive for 3R tau in SN. 3R tau IR was more predominant in HF, IC, PC, LC, CGM and RPN, which replicates AD-like distribution partly shared with typical PSP. Rectangle in the right upper corner labeled as AD encompasses AD-type pathology in terms of distribution, further characterized by dominance of 3R tau and lack of TAs. The left lower area labeled as PSP encompasses PSP-type pathology in terms of distribution with 4R selectivity not only on TAs but also on NFTs. Although this chart provides concise and operational sorting of tau-positive lesions into AD or PSP origins, it is still difficult how to sort STN, M-TEG and P-TEG into PSP or AD (dotted area), because a few lesions exhibited 4R tau IR