Figure 4. Spatial learning deficit in CBKO mice.

A) Schematic representation of the active place avoidance task: The active place avoidance task involves placing the mouse on a rotating platform, open to visual cues within the room. A stationary 60° region of the room is designated as the shock zone. An overhead camera is used to track the movement of the mouse during the trial session. B) The average number of times animals from each group entered the shock zone averaged across all 9 training trials. Both young and middle aged/old CBKO mice entered the shock zone significantly more often than WT mice. (p<0.05) (means ± SEM). C) Distance traveled by each group averaged across habituation and all 9 training trials. Individual t tests confirmed that middle-aged/old CBKO mice walked a significantly shorter distance on the rotating platform than middle-aged/old WT controls. Young CBKO and WT mice did not differ on this measure (p<0.05) (means ± SEM). D) To control for movement differences between the groups, the number of shock zone entrances each animal made per meter traveled was calculated and averaged across all 9 training trials. The results confirm our finding that both young and middle-age/old CBKO mice entered the shock zone significantly more often than WT mice. (p<0.05) (means ± SEM).