HuD KO mice perform poorly in Morris water maze and spend more time in the open arms of the elevated plus maze. A, Average latency to find a visible platform by genotype in five trials of the Morris water maze. B, Average latency to find a hidden platform by genotype in four consecutive days of testing, five trials per day. C, Average total time spent in the enclosed and open arms of the elevated plus maze by genotype. D, Proportion of total time spent in the open arms of the elevated plus maze by genotype.