Fig. 4

RD4 and RD3 DAB immunohistochemistry. Representative adjacent sections of the same cases as those shown in Fig. 2 underwent DAB immunohistochemistry with RD4 or RD3. From top to bottom: the midbrain of case 5, 10, and 23, and the pons of case 3, 10, 23, with cortical NFT stages I/II, III/IV, V/VI, respectively. Insets in the images above (a-d, i-l, q-t) correspond to the area shown in the images below (e-h, m-p, u-x) for each section. The results of DAB immunohistochemistry were in line with the findings based on immunofluorescence that the proportion of 3R tau positive NFTs in the midbrain increased with advancing NFT stages while the proportion of 3R tau positive NFTs in the pons was high already in early stages. Scale bar = 500 μm (a-d, i-l, q-t), 100 μm (e-h, m-p, u-x)