Figure 3

Spatial learning and memory analyses using Barnes circular maze test in mito-mice. (A) Training course. Latency (P = 0.7381), number of errors (P = 0.5051), and distance traveled (P = 0.7885) to target hole for low (black) and high (gray) groups were plotted. (B) Probe tests at 24-h, 7-day, and 36-day after the last training. There was no significant difference in the probe test at 24-h (between the target hole and right side hole, P < 0.005 in the low and P < 0.001 in the high groups; between the target hole and left side hole, P < 0.05 in the low and P < 0.002 in the high groups) and 7-day retention intervals (between the target and right side holes, P < 0.001 in the low and P < 0.001 in the high groups; between the target and left side holes, P < 0.05 in the low and P < 0.002 in the high groups). In the probe test at the 36-day retention interval, single and double asterisks indicate significant differences between the target and right side holes in the low group (P < 0.02 in the low and P = 0.9804 in the high groups) and between the target and left side holes in the low group (P < 0.0001 in the low and P = 0.2106 in the high groups), respectively. (C) A single retraining after the probe test at the 36-day retention interval. Each score of individual mito-mice in the low (black) and high (gray) groups were plotted against the proportion of ΔmtDNA in the tails at age 4 weeks. Mice 52, 64, and 76 carried 52%, 64%, and 76% ΔmtDNA, respectively. Pearson’s product-moment correlation coefficients and the associated probabilities are indicated as R and P, respectively. All values are means ± SE.