Fig. 1.
ARM deficits in drk mutant heterozygotes. Performances of mutants are indicated by open bars and controls by black bars. The mean ± SEM are shown. Following ANOVA, potential differences among controls and mutants were assessed for significance with least square means contrast analyses. (A) Three-minute memory of drkΔP24/+ animals after 12 US/CS conditioning once was not significantly different (P = 0.23, n = 8 each) than that of controls. (B) Three-hour memory (left side of the graph) of the null heterozygotes of single 12 US/CS session conditioning was significantly different from controls (P < 0.001, n = 7). Significant differences (P < 0.0013, n = 7) in 3-h ARM were also revealed following cold shock (right side of graph as indicated). (C) Partitioning the 3-h memory of drkΔP24 heterozygotes and controls into ARM and ASM by subtracting from normal 3-h memory that after cold shock. ASM (black) is nearly identical, but ARM is highly reduced in drkΔP24 heterozygotes. (D) ARM induced after 5× massed training and assessed 24 h later was significantly different in drkΔP24/+ (P < 0.007, n = 9) and drkE0A/+ (P < 0.005, n = 7) than controls. (E) In contrast, 24-h LTM induced by 5× spaced training was not affected (P = 0.9, n = 14 for drkΔP24/+; P = 0.78, n = 12 for drkE0A/+).