Ameliorative effects of brief daily periods of social interaction on isolation-induced behavioral and hormonal alterations

The present study investigated the effects of brief daily periods of social interaction on social-isolation-induced behavioral and hormonal alterations and deficits. Adult male Wistar rats were allocated to one of three housing conditions: 1) social housing (two per cage); 2) social isolation (one per cage); or partial social isolation (one per cage with access to another male rat for 60 min/day). After 14 days in these different housing conditions, the animals were subjected to various behavioral tests, including sucrose preference test, acoustic startle response, two-way active shuttle avoidance, pre-pulse inhibition, open field, cooperation learning task, and levels of corticosterone. Results revealed that social isolation had a substantial impact on rats' performance on most behavioral tests as well as on their corticosterone levels. Importantly, however, the results clearly demonstrate that allowing otherwise isolated animals to have a brief (60 min) daily social contact with another rat to a great extent abolishes or ameliorates most of the isolation-induced behavioral and hormonal alterations. Hence, providing isolated animals with brief daily periods of social contact may be used as a "preventive treatment" in order to protect them from the deleterious effects of isolation. (C) 2013 Elsevier Inc. All rights reserved.