Figure 4.

Distance traveled in an open field (OF) for Experiment 2 on day 1 (pre-IMO and post-IMO period) and day 8 (retention). Means and SEM are represented. The groups were: control-OF, which were exposed to the OF for 5 min, left undisturbed in their home-cages in the animal room for 25 min and then returned to the OF for an additional 90 min period (R 0–90); IMO-home, which were allowed to explore the OF for 5 min, then exposed to IMO inside the OF for 25 min and finally returned to their home-cages in the animal room; and IMO-OF groups, which were treated as the previous group but were released from the IMO board and maintained in the same OF for an additional post-IMO period of 90 min. On day 8, activity was evaluated in three time blocks of 5 min each. ^***p < 0.001 vs. control-OF group, regardless of time.