Figure 4.

Aged rats were separated into those that were unimpaired (AU^tEBC; N=15) or impaired during trace conditioning (AI^tEBC; N=16). A) Both AU^tEBC and AI^tEBC animals decreased their path length across the five sessions of hidden platform training, whereas young rats consistently had shorter path lengths than either of these groups. Inset: All three groups displayed comparable path lengths during visible platform training. B) Cumulative distributions of average path length during the last three sessions of hidden platform training. C) Average proximity across the three probe tests. There was no difference in average proximity between aged rats that were unimpaired during trace conditioning and young rats. However, aged rats that were impaired during trace conditioning had greater proximity measures than young animals, confirming that these rats were also impaired during water maze probe testing. D) Cumulative distributions of average proximity across the three probe tests. Together, these results reveal that aged rats that were impaired during trace conditioning were also impaired during water maze probe testing. Aged animals that were unimpaired during trace conditioning were unimpaired during probe testing. Dotted lines indicate median of cumulative distributions. Error bars represent standard error of the mean.