The effect of environmental enrichment on spatial learning and expression of cyclic AMP response element binding protein from mouse hippocampus
The present research was undertaken to investigate the effects of physical and/or social enrichment, and sensitive periods on spatial learning. Additionally, levels of the transcription factor cyclic AMP response element binding protein (CREB) were analyzed from the hippocampus of sample animals. There were four groups of C57BL mice, one individually housed and 3 socially housed. Animals in both treatment (i.e., enrichment) groups were housed collectively and received physical enrichment at one of two periods (early, days 35-94, or late, days 100-159). Upon completion of behavioral testing, expression of CREB from the hippocampal tissue of representative animals was assessed by Western blot analysis. At the final testing period, all socially housed animals, both experimental groups and the control group, had significantly shorter latencies to find the hidden platform than did the individually housed control group. Further, both experimental groups were significantly better at the water maze than was the control socially housed group, and finally, the animals that received enrichment during the first enrichment period (days 35-94) demonstrated significantly better performance in the water maze during the second testing period than did the other three groups and greater expression of CREB in the hippocampal tissue was suggested in the representative animals from the early enrichment group than both control groups and the late enrichment group.