Figure 7.
Disruption of WRP anchoring to WAVE affects memory retention. A–F, Analysis of spatial learning and memory performance of wild-type (wave+/+), heterozygous (wave+/m), and knock-in (wavem/m) mice in the Morris water maze (n = 10 each genotype; mean ± SEM value is shown). A, Time to swim to the platform (latency) was measured for wild-type (squares), heterozygous (diamonds), and knock-in (circles) mice. The mice were tested in two daily sessions of three trials each. Sessions 1–4 are learning trials for the visible platform, and sessions 5–10 are learning trials for the hidden (submerged) platform. No significant differences were observed in the learning curves. B–F, Memory retention after learning trials was measured in probe trials (platform removed). The percentage of time spent searching in the target quadrant (quadrant containing platform during sessions 5–10) versus nontarget quadrants was measured. **p < 0.01 target versus any other quadrant using one-way ANOVA. Probe trials were conducted 2 h after session 6 on day 3 (B) (wave+/+, p = 0.0012; wave+/m, p = 0.0035), session 8 on day 4 (C) (wave+/+, p < 0.0001; wave+/m, p < 0.0004), and session 10 on day 5 (D) (wave+/+, p < 0.0001; wave+/m, p = 0.0026; wavem/m, p < 0.0001). E, F, A delayed probe trial was conducted 14 d after session 10 to measure long-term memory retention. E, Representative swim-trace patterns for wild-type (wave+/+, left) and knock-in (wavem/m, right) mice in the delayed probe trial. Start position is marked by a black square, and a circle marks target location. F, Quantification of percentage time spent searching in each quadrant during the delayed probe trial (wave+/+, ***p < 0.0001; wave+/m, **p = 0.005). G, Nonspatial learning and memory was measured by novel-object recognition (n = 10 each genotype; mean ± SEM value is shown). Graph shows percentage time spent exploring the novel object for wild-type (wave+/+), heterozygous (wave+/m), and knock-in (wavem/m) mice. *p = 0.036 using one-way ANOVA; Tukey–Kramer, p < 0.05 wild-type versus knock-in.