Influence of aging and enriched environment on motor activity and emotional responses in mice

We have evaluated different behavioral parameters in ICR (CD1) female mice of three different ages (38-39 weeks: mature; 62 weeks: late mature; 90 weeks: old), and addressed the effects of an enriched housing condition. We employed the following battery of tests: Holeboard, open field, elevated plus-maze (EPM), and forced swimming test (FST). The results suggest that aging process differentially affects diverse aspects of behavior. With respect to motor activity, late mature animals were more affected by enrichment, whereas old animals appeared to be more affected when emotional responses were considered. We propose that the diminished percentage of time in the open arms of the EPM showed by enriched mice may be indicative of decreased novelty seeking, whereas their decreased climbing behavior may indicate a reduced escape-related behavior in an inescapable situation.