Figure 4.

Impaired associative memory in EC-SOD transgenic mice. A, Freezing behavior was expressed as the percentage of time during training (train) and testing (test) for 3-month-old wild-type (WT) and EC-SOD transgenic (EC-SOD TG) mice. Bar graphs on the left show the percentage of time that the mice froze to context 24 h after training. Bar graphs on the right show the percentage of time that the mice froze to the auditory cue 25 h after training. (WT, n = 7; EC-SOD TG, n = 10). Data are plotted as mean ± SEM. ∗∗∗p < 0.001 compared with aged wild-type mice by Student's t test. B, Similar to A, except that aged (>20 months of age) mice were used for this study (WT, n = 20; EC-SOD TG, n = 22).∗p < 0.05 compared with aged wild-type mice by Student's t test.