Figure 2. Cognitive function deficits in Zic2^kd/+ mice.

(A) Morris water maze test. (top) Mean latency to reach the platform during the training session (days 1–4) and reverse test session (day 6). Values indicate the mean of all six trials on the day. (middle left) Moving speed in the training session. (middle right) No movement time in the training session. (bottom) The results of the probe test (day 5) as indicated by the period of time (s) in the indicated quadrant within the 60 s testing period. *P < 0.05 in t-test. (B) Fear conditioning test. Mean percentage freezing are indicated for the conditioning test (day 1) before and after the electrical foot shock (preUS [mean of the 2 min before unconditioned-stimulus, US] and US [1 min after US] respectively), context test (day 2, mean of the total testing period [5 min]), and cue test (day 3) before and after pre tone (preCS [mean of the 2 min before conditioned stimulus, CS] and CS [mean of the 2 min with CS], respectively). *P < 0.05 in Mann-Whitney U-test. (C) Y-maze test. (left) Percentage altered selection of the entered arm. (right) Total number of arm entries. *P < 0.05 in Mann-Whitney U-test; **P < 0.01 in t-test. Data is presented as means ± SEM. The number of mice in each group is given in parentheses.