Figure 2.

Ablation of DCX⁺ cells impairs performance of the active place avoidance task; repopulation of DCX⁺ cells rescues acquisition of the task. A, Schematic representation of the active place avoidance task. Experimental mice were placed on top of a turntable, confined in a clear circular barrier. Using distal visual cues as a reference, the animals were trained to avoid a stationary shock zone (red triangle). B, Depiction of the path tracked by the experimental mice (gray line) within the arena during habituation (top) and after trial day 3 of training (bottom). Red line indicates shock zone of 60°; small red circles represent “shocks” delivered. C, Experimental design used to assess the importance of DCX⁺ cells for learning and memory in the active place avoidance task. D, Acquisition of the active place avoidance task was significantly impaired in DCX^DTR mice 3 d after DT treatment. DCX^DTR mice received more shocks than control mice (left: F_(1,22) = 17.37, p < 0.001), had shorter maximum shock zone avoidance time (middle: F_(1,22) = 12.81, p < 0.01), and had a higher number of entries into the shock zone per distance covered (right: F_(1,22) = 15.06, p < 0.001). E, At 45 d after ablation (i.e., after recovery of the DCX⁺ cell population), the DCX^DTR mice performed as well as control animals in the new active place avoidance task. There was no difference observed in the number of shocks received (F_(1,22) = 1.23, p = 0.28), maximum avoidance time (F_(1,22) = 0.76, p = 0.39), or entries per distance (F_(1,22) = 0.56, p = 0.46) between genotypes. S indicates experimental session (i.e., S1, Session 1). **p < 0.05, Significance between genotypes for individual trial days (Bonferroni post hoc test). n = 12 per experimental group.