Fig. 2.

Assessment of behavioral learning. (A) Spatial learning in Morris water maze tests. Mean time to find a submerged platform (latency) is shown as a function of trial day. Data were collected in four different experiments involving 40 WT (+/+) and 30 KO (−/−) mice. Error bars in this experiment and all other experiments represent SEM values. (B) After removal of the platform on the indicated day, the number of times animals of the two genotypes swam across the former location of the platform was determined. (C) Associative learning in cued conditioning fear tests. Percent freezing was measured in response to an auditory cue 1 h after the training period (Upper left) and 24 h after training period (Lower left), or in response to the context in which the training was performed after 1 h (Upper right) or 24 h (Lower right). Data were collected in two different experiments involving 30 +/+ mice and 30 −/− mice. (D) Motor learning in rotating rod tests. The mean times mice of the indicated genotypes stayed on the rotating rod are plotted as a function of trial day. Data were collected from 15 +/+ and 15 −/− mice.