Correlation of immunolabeled LM and EM images of CBD-pretangles. Reticular tau immunoreactivity in the cytoplasm in a pretangle neuron of CBD (case 3) labeled with anti-tau antibody (AT8) visualized with QD 655, also labeled with Alexa 488 for more precise confocal images (A). When compared between LM (B) and its exact EM counterpart, reticular tau immunoreactivity in the cytoplasm (C, rectangle e) was composed of randomly distributed straight filaments (E, arrowheads). Tau immunoreactivity in the dendrite (C, rectangle d) on LM corresponded to a few 15-nm straight filaments assembled roughly in parallel. Their arrangement was less tight than that in NFTs in AD. Scale bars in A-C = 10 μm; D = 250 nm; E = 500 nm.