Impoverished rearing conditions increase stress-induced irritability in mice

Irritability was tested in mice reared in four environmental conditions: impoverished (IC), impoverished + overstimulated (ICS), enriched (EC), and enriched + overstimulated (ECS) conditions. The test used was a modified "bottle brush" test. Both overstimulations and individual housing increased irritability interacting positively with each other. Individual housing but not overstimulation decreased avoidance behavior in the mice.