Fig. 3

White matter degeneration and pathology burden in FTLD-Tau and FTLD-TDP. Photomicrographs depict representative images of group-level observations from myelin stain (LFB) and phosphorylated tau (AT8) in FTLD-Tau (A-H) or phosphorylated TDP-43 stained tissue in FTLD-TDP (I-P) from adjacent sections of middle frontal cortex white matter (WM). FTLD-Tau (CBD = A-B; PiD = C-D; PSP = E–F, MAPT = G-H) showed a greater frequency of tissue with moderate to severe WM degeneration with reduced LFB stain and disorganized fibers, which was accompanied by largely moderate to severe tau-positive axonal threads (asterisks) and glial tau inclusions (arrows); whereas FTLD-TDP (TDP subtype A = I-J; TDP subtype B = K-L, TDP subtype C = M–N, TDP subtype E = O-P) showed a greater frequency of normal to mildly degenerated WM on LFB stain with negligible or slightly reduced LFB stain and disorganization, and accompanied by relatively mild to moderate density of TDP-43 positive oligodendrocytes (arrows) and rare diffuse threads (asterisks). Scale bar = 50 µm. Legend: CBD = corticobasal degeneration; FTLD-Tau = frontotemporal lobar degeneration with inclusions of the tau protein; FTLD-TDP = frontotemporal lobar degeneration with inclusions of the TDP-43 protein; LFB = luxol fast blue; MAPT = tau with MAPT gene mutation; PiD = Pick’s disease; PSP = progressive supranuclear palsy; TDP A/TDP B/TDP C/TDP E = subtypes of FTLD-TDP pathology