Impaired motor coordination, hyperactivity, and stereotypes in Cdkl5 +/− female mice. (a, b) Rotarod assay, measuring latency to fall (a) and frequency of passive rotations (b; rotations in which the mouse does not perform any coordinated movement but is passively transported from the rotating apparatus) on the accelerating rotating rod. Testing was performed in 4 trials with an intertrial interval of 1 h. Cdkl5 +/− (n = 21) and Cdkl5 −/− (n = 23) mice showed a decreased latency to fall (a) and an increased frequency of passive rotations compared to Cdkl5 +/+ (n = 17) mice, indicating impaired motor coordination in Cdkl5 +/− and Cdkl5 −/− mice. (c, d) Locomotor activity measured as total distance traveled (c) and average locomotion velocity (d) during a 20 min open-field test. Cdkl5 +/− (n = 19) and Cdkl5 −/− (n = 22) mice exhibited increased locomotor activity with a longer total distance traveled (c) at a greater average speed (d) compared to Cdkl5 +/+ (n = 16) mice. (e) Number of stereotypic jumps (repetitive beam breaks < 1 s) in the corners of the open-field arena during the 20 min trial. Cdkl5 +/− (n = 19) and Cdkl5 −/− (n = 21) mice showed an increased number of repetitive stereotyped jumps compared to Cdkl5 +/+ (n = 15) mice. (f) Time (cumulative duration) spent by the border, near the walls, and in the center of the open-field arena. Cdkl5 +/+, Cdkl5 +/−, and Cdkl5 −/− mice spent a comparable time at the border, near the walls, and in the center compared to controls, suggesting that hyperactivity was not due to increased anxiety. Values represent mean ± SEM. ∗
p < 0.05, ∗∗
p < 0.01, and ∗∗∗
p < 0.001 (datasets in (a–d, f), Fisher's LSD test after ANOVA; datasets in (e) Dunn's test after Kruskall-Wallis).