Treatment with Aβ12-28P rescues APPK670N/M671L mice from memory decline. Aβ12-28P-treated APPK670N/M671L mice performed comparably to WT, age- and sex-matched littermates on radial arm maze testing. Both groups performed statistically better than APPK670N/M671L mice treated with vehicle; ANOVA P < 0.0001, post hoc Aβ12-28P vs. WT nonsignificant, Aβ12-28P vs. vehicle P < 0.001, WT vs. vehicle P < 0.001 (n = 11 for vehicle and Aβ12-28P-treated Tg groups, n = 12 for WT).