Research Paper Volume 15, Issue 13 pp 6031—6072

Figure 3. Enrichment reduces novelty-induced locomotion in aged mice. In the Aged groups an RM-ANOVA showed an effect of Time for all groups on the distance travelled (F(5,260) = 27.53, p < 0.0001) indicating a reduction in activity over time. There was also a Time x Housing effect (F(52,260) = 6.25, p < 0.0001), but the Simple Main Effects showed this was significant only for the first 10 minutes of the OF between WTSH and WTEE (p = 0.025), but not between KDSH and KDEE (p = 0.077). Following the introduction of an object (broken vertical line) an analysis of the novelty-induced locomotor shift was carried out comparing levels of activity during the first 10 minutes from the introduction of the object with the last 10 minutes of the open field. A significant effect for both Genotype and Housing was found (F(1,52) = 4.71, p = 0.035 and F(1,52) = 10.34, p = 0.002, respectively) indicating a greater effect of novelty in the enriched animals and in the MSK1 KD mutants. In the open field + object phase of the trial, an RM-ANOVA showed an effect of Time for all groups (F(5,260) = 132.43, p < 0.0001) reflecting a reduction in activity over time. There was a Time x Housing and a Time x Genotype effect (F(52,260) = 10.43, p < 0.0001 and F(52,260) = 4.20, p = 0.001, respectively) and also a Genotype effect; F(1,52) = 5.78, p = 0.020 indicating a greater activity in the MSK1 KD mutant mice, and with lower levels of activity in the enriched WT mice. The data are presented as distance travelled in metres as cumulative distance reported in 10 min intervals. Each phase lasted 60 min (120 min in total). Datapoints are presented as mean ± SEM. Heatmaps below the graphs depict the arena occupancy in the open field ± object stages for the mice of each group.