Figure 5.
D664A mutation prevents learning deficits observed in PDAPP(J20) animals. Animals were trained for 4 d (2 sessions per day) in a hidden platform Morris water maze. Distance to platform (in centimeters) and latency to platform were measured; however, only distance is shown. A, At 3–4 months, PDAPP(J20) mice appeared to show longer distance-to-platform measurements in the last four sessions, but the data did not reach statistical significance. B, D664A(B21) animals learn normally. C, At 8–12 months, PDAPP(J20) mice show significant learning impairments (**p < 0.0001; n = 19). Probe trials were not significantly different between groups at either age (data not shown). D, At 8–12 months, D664A(B21) mice do not show any learning impairment. NTg, Nontransgenic.