FIGURE 9.

Plaque and tangle pathologies visualized by multiple labeling methods in adjacent sections of the visual cortex (VC) in an AD brain exhibited Thal phase 5 and Braak stage VI neuropathologies. Section orientation, figure panel arrangement, regional/laminar organization, and scale bars are as indicated. The blue broken lines mark the border between areas 17 and 18. Sorfra plaques are present in both areas 17 and 18, but appear more frequently in the latter (A–C). They are largely located over layers II–IV, including the three sublayers of IV in area 17 (B–D). (E–H) Aβ immunolabeling in a neighboring section, with compact and diffuse plaques densely packed in both visual cortical regions. In area 17, a large amount of β-amyloid deposition in layers IVa–IVc appear to be diffuse-like plaques, whereas the lesions in layers II–III, V, and VI in areas 17 and 18 appear to be large compact-like (E–H). Leptomeningeal Aβ deposition is also evident in both regions (A,F,H). (I–L) BACE1 immunolabeling at low and high magnifications, with the pathological profiles appearing as dystrophic neurites arranged as clusters or isolated swollen neurites located over layers II–VI (J–L). (M–P) Low- and high-magnifications of silver-stained neuritic plaques in the primary and secondary visual cortical areas. At high magnification, the neuritic clusters are largely distributed in layers II–VI in both areas 17 and 18. In the deep cortical layers (IV–VI), silver-stained neuronal processes are present in both areas, most of which are oriented perpendicularly relative to the cortical surface (N–P). (Q–T) pTau-labeled neuronal somata and neurites clearly present in both areas 17 and 18. The overall amount of labeled profiles appears to be greater in area 18 than in area 17, with layers II–III exhibiting a denser labeling relative to IV–VI. There is a noticeable variability in the amount of labeling across area 17, with the cortical part lying around the deeper part of the calcarine sulcus (cs) contained denser labeling relative to the part surrounding the superficial part of the cs (Q). Note that this regional variability in pTau reactivity is also noticeable for the amount of sorfra plaques across area 17 (A). At high magnification, pTau-labeled neuronal processes can arrange as densely packed neuritic clusters, with tangled neuronal somata distributed between the fine and swollen neuritic profiles (T, as pointed by arrows). Referring to Figure 4 for all abbreviations.