CHANGES IN SOCIABILITY AND PREFERENCES FOR SOCIAL NOVELTY IN FEMALE RATS UNDER PROLONGED SOCIAL ISOLATION

Chronic social isolation (SI) stress may lead to distress with negative outcomes in humans and an¬imals. The many disorders caused by SI include emotion and motivation impairments, cognitive decline, and social behavior alterations. Currently, there is no data on the consequences of SI when its duration is significantly prolonged. Despite female rats being more sensitive to stress, insufficient research was conducted on them. In this study, we assessed sociality (sociability) and novel social object preference in the three-chamber social test in female Wistar rats in two series of experiments at different periods of SI starting from adolescence and lasting up to the age of 5.5 and 9.5 months. After 2 months of SI, the rats showed increased social object preference versus non-social object (higher sociability) while novel social object preference versus familiar social object was decreased (indicating lower social novelty preference). In the social interaction test, the rats also spent more time engaging in social contacts, including aggressive behavior, showed lower levels of exploratory head-dipping over the open arms in the Elevated Plus Maze test, and reduced exploratory behavior. After 8.5 months of SI, we observed a sociability deficit and a profound reduction in novel social object preference. We registered no changes in aggressive behavior. To conclude, the effects of SI on social behavior depended on its duration, and we believe that these effects were associated with changes in coping strategies.