Spatial memory deficits in Lrrtm1 KO mice.

(A) Morris water maze training session. The total distance swum before reaching the target was significantly greater in KO mice than in WT mice on the first day, whereas it was comparable to that in WT mice on the second to fourth days. Values are presented as means ±SEM. * P<0.05; ** P<0.01. (B, C) Morris water maze probe test. Both the time spent in the target quadrant (B) and the number of crossings over the targets (C) were lower in Lrrtm1 KO mice than in WT mice. Dotted line indicates the chance level. Values are presented as means ±SEM. * P<0.05 in U-test.