Open-field activity. Data are mean ± SEM values from 19 wild-type and 20 PKCε-null hybrid mice. (a) Locomotor activity in the center varied as a function of genotype (F_1,38 = 5.1, P < 0.05) and test day (F_2,64 = 26, P < 0.001) (two-way repeated measures ANOVA). *P < 0.05 compared with wild-type mice on the same day (Tukey’s test). Activity also varied by test day in the periphery (b) (F_2,64 = 37.2, P < 0.001) and total field (c) (F_2,64 = 38.6, P < 0.001), but not by genotype in these areas. Activity on days 2 and 3 was different from that on day 1 regardless of genotype or area (Tukey’s test, P < 0.05). (d) The percentage of total distance traveled in the center varied by genotype (F_1,38 = 5.7, P = 0.022) and test day (F_2,64 = 12.7, P < 0.001) and was less on days 2 and 3 compared with day 1 (Tukey’s test, P < 0.05). (e) The percentage of time spent in the center varied by genotype (F_1,38 = 8.1, P = 0.007) and test day (F_2,64 = 5.8, P = 0.005), and was less on day 3 compared with day 1 (Tukey’s test P < 0.05). *P < 0.05 compared with wild-type mice on the same day (Tukey’s test).