Strikingly at 6 months, the tg-AD mice with WT PKCα (WT tg-AD) had normal cognition, but the presence of the M489V mutation (M489V tg-AD) abolished the ability of the mice to discriminate between the target quadrant (filled bars) and the other quadrants (open bars) (Fig. 6b). This evidence concerns the gene PRKCA and Alzheimer disease.