Figure 6.

Axon density is not reduced near plaques. SMI312-positive axon immunoreactivity was quantified in Tg2576 cortex and control cortex. The ratio of staining intensity was compared in a 50 × 50 μm square region of interest adjacent to a plaque (stained blue with thioflavine S) and in an identical region 100 μm away. In control images, SMI312 immunoreactivity was measured adjacent to a phantom plaque (circle) and a site 100 μm away. There is no difference in this ratio between Tg2576 (a) and control cortex (b). In both conditions, the ratio is very close to 1 (1.03 ± 0.10 in Tg2576 cortex; 1.05 ± 0.05 in control cortex), indicating no difference in SMI32-positive axon density near plaques. Scale bar, 50 μm.