I think it is difficult to find a "standard" for enrichment of rats. In general at best the distinction between exercise (running wheel) and "enrichment is made. But often these also applied together. In a study(http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0011943) we showed that both forms of enrichment( with and without running wheel) have anxiolytic properties however, there are some studies that show differences between exercise and enrichment (for example : http://learnmem.cshlp.org/content/18/9/605.short

also see: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016643)

Regards,

Erik

So many thanks