NG2-positive OPCs were widely distributed throughout the hippocampus of both 3xTg-AD and non-Tg mice (Fig. 1Ai-iv), and cell counts indicated there was a decrease in the overall numerical density of OPCs between 6 months and 24 months in both 3xTg-Ad and non-Tg controls (Fig. 1Av, unpaired t-tests). This evidence concerns the gene CSPG4 and Alzheimer disease.