Human AD brains exhibited substantially diminished synapsin I and PSD95 staining, but prominently elevated 3B3 labeling immediately beyond the halo edge (Fig. 4b), compared with brain regions either far from the plaque cores (>50 μm; Fig. 4c) or in the non-demented controls (Fig. 4d). This evidence concerns the gene SYN1 and Alzheimer disease.