Effect of a sedentary period and reactivating exercise on 2 wk exercise-enhanced long-term object location memory. (A) Experimental schematic. Mice were given access to a running wheel for 2 wk. Mice were then split into groups and returned to their home cages for either 3, 7, or 14 d. Mice were then either immediately trained and tested for OLM, or given access to running wheels for another 2 d (reactivation exercise) prior to OLM training and testing. OLM testing was performed 24 h after training. All mice were habituated to the OLM chamber for the 6 d prior to OLM training. (B) The mean total distance run by mice in each experimental group during the 2 wk exercise period. There was no significant difference in the amount of exercise each group received during this period. Distance data from 2 wk exercise mice presented in Figure 1B also shown for comparison. (C) The mean total distance run by mice that underwent 2 d reactivation exercise. There was no significant difference in the amount of exercise each group received during this period. Distance data from Figure 1B also shown for comparison. (D) Mean time spent attending to objects during OLM training. Data from Sedentary and 2 d exercise controls presented in Figure 1C are also shown for comparison. There was no difference between the groups. (E) Mean DI for each group during OLM training. Data from Sedentary and 2 d exercise controls presented in Figure 1D are also shown for comparison. Mice showed no preference for objects during training. (F) Mean time spent attending to objects during OLM testing. Data from Sedentary and 2 d exercise controls presented in Figure 1E are also shown for comparison. There was no difference between the groups. (G) Mean DI for each group during OLM testing. Data from Sedentary and 2 d exercise controls presented in Figure 1F are also shown for comparison. Mice that run for 2 wk followed by either a 3, 7, or 14 d sedentary period show a significant decrease in preference for novel object location, compared to mice that run for 2 wk with no sedentary period. Mice that then receive a 2 d period of reactivation exercise following either 3 or 7 sedentary days show a significant increase in novel object preference during testing compared to training. However, 2 d of reactivation exercise is not sufficient to significantly improve object location memory in mice that have had a sedentary delay period of 14 d. All data shown is mean ± SEM. Between-groups comparisons denoted by *'s, within-group comparisons denoted by #'s. (*) P < 0.05, (**/##) P < 0.01, (***/###) P < 0.001.
