Figure 4.

MSK1 knock-out mice have impaired passive avoidance and spatial learning. A, Latency times for wild-type (n = 23) and MSK1 knock-out mice (n = 13) to step into the dark compartment of the training chamber in the passive avoidance task. MSK1 knock-out mice have significantly shorter latency time on day 2 after training. B, Plot of latency times to find the escape platform for wild-type (n = 14) and MSK1 knock-out mice (n = 18) over eight trial blocks in the Morris water maze. C, Time spent in each quadrant of the Morris water maze pool for wild-type (n = 14) and MSK1 knock-out mice (n = 18) during the probe trial. MSK1 knock-out mice spent significantly less time in the target quadrant than wild-type mice, lacking a spatially selective search strategy. D, Number of platform crossings in each quadrant for wild-type (n = 14) and MSK1 knock-out mice (n = 18) during the probe trial. MSK1 knock-out mice had significantly fewer platform crossings in the target quadrant than wild-type mice. Error bars indicate SEM. Asterisks denote a significant difference (p < 0.05) as determined by Tukey's multiple-comparison test.