Rearing Environmental Enrichment in Two Inbred Strains of Mice: 1. Effects on Emotional Reactivity

• Published in: Behavior genetics Vol. 29; no. 1; pp. 41 - 46
• Main Authors: Chapillon, P., Manneché, C., Belzung, C., Caston, J.
• Format: Journal Article
• Language: English
• Published: United States Springer Nature B.V 01.01.1999
• Subjects: Analysis of Variance; Animals; Animals, Newborn - genetics; Animals, Newborn - growth & development; Animals, Newborn - psychology; Anxiety - genetics; Environment; Exploratory Behavior - physiology; Female; Housing, Animal; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Play and Playthings; Reactivity; Temperament - physiology; Tests; Trait anxiety
• ISSN: 0001-8244; 1573-3297
• DOI: 10.1023/A:1021437905913

The effects of an enriched rearing environment on two types of anxiety-like behavior (designated "trait" and "state" anxiety) and on spontaneous activity were investigated in two inbred strains of mice, BALB/c (C) and C57BL/6(B6). Subjects were socially reared from birth to 56 days of age under enriched or standard rearing conditions. The enriched environment consisted of an assembly of plastic boxes in which a various number of objects (running wheels, pieces of plastic, etc.) offered the possibility of multiple activities. The subjects were subsequently tested in three situations: a spontaneous activity recorder, an elevated plus-maze test (a model of state anxiety), and a free exploration test (a model of trait anxiety). No group differences could be found in spontaneous activity. Environmental enrichment, however, decreased the level of both types of anxiety-like behavior in the C strain. In contrast, the level of trait anxiety of the B6 mice was not modified. The results were discussed in relation to possible CNS modifications, especially in the limbic system.