Social interactions in adolescent and adult Sprague–Dawley rats: Impact of social deprivation and test context familiarity

Abstract

Interactions with peers become particularly important during adolescence, and age differences in social interactions have been successfully modeled in rats. To determine the impact of social deprivation on social interactions under anxiogenic (unfamiliar) or non-anxiogenic (familiar) test circumstances during ontogeny, the present study used a modified social interaction test to assess the effects of 5 days of social isolation or group housing on different components of social behavior in early [postnatal day (P) 28], mid (P35), or late (P42) adolescent and adult (P70) male and female Sprague-Dawley rats. As expected, testing in an unfamiliar environment suppressed social interactions regardless of age, housing, and sex. Social deprivation drastically enhanced all forms of social behavior in P28 animals regardless of test situation, whereas depriving older animals of social interactions had more modest effects and was restricted predominantly to play fighting-an adolescent-characteristic form of social interactions. Social investigation-more adult-typical form of social behavior was relatively resistant to isolation-induced enhancement and was elevated in early adolescent isolates only. These findings confirm that different forms of social behavior are differentially sensitive to social deprivation across ontogeny.

Infantile experience and play motivation

“…Similar profound although transient disruptive effects have been reported using aversive manipulations such as predator threat, food deprivation, physical immobilization, intense light conditions, and unfamiliarity with the play chamber: all examples of the inhibitory action of aversive states on play motivation (Klein, Padow, & Romeo, 2010;Panksepp et al, 1984;Siviy & Harrison, 2008;Siviy & Panksepp, 1985;Siviy, Harrison & McGregor, 2006;Thor & Holloway, 1984a;Vanderschuren et al, 1995;Varlinskaya & Spear, 2008) that have contributed to spread the idea that R&T is a labile and fragile behavior. Klein et al (2010) recently observed that pins and dorsal contacts disappeared in 20 min after termination of a severe stressor-30 min of physical restraint-although they returned rapidly to their normal levels after 60 min.…”

“…Yet it could be that a lack of signs of visceral upset does not necessarily imply that H and NH groups dealt with the testing procedure in the same way, as the differential impact of an unknown situation on rats' behavior in the two groups could as well depend on other factors related to familiarity (e.g., Thor & Holloway, 1984a;Vanderschuren et al, 1995;Varlinskaya & Spear, 2008). For this reason, Part 3 was conceived to evaluate whether groups with different experience (familiarization) with the play chamber would show differences in the amount of R&T, as well as whether such differences would be larger (or not) in NH groups than in H groups.…”

“…In Part 2, the objective is to delineate the limits in the amount of R&T that the rats are capable of exhibiting by extending the length of social deprivation over six consecutive days and to explore whether the NH rats' comparatively low pinning rates could be increased by housing them with H partners during a cohabitation period lasting from weaning to the start of the experiment (contagion effect: Pellis & McKenna, 1992. In Part 3, the objective is to determine whether familiarity with the experimental situation has independent or interactive effects with early handling on R&T (Thor & Holloway, 1984a;Vanderschuren, Niesink, Spruijt, & Van Ree, 1995;Varlinskaya & Spear, 2008). In Part 4, the objective is to obtain evidence of the suppressing effects of an unexpected contextual change on R&T in H and NH rats.…”

Effects of physical exercise and social isolation on anxiety-related behaviors in two inbred rat strains

“…No significant effects were observed in the EPM (Table 2). Rats usually live in groups and have high contact with other rats to establish their social organization (Varlinskaya & Spear, 2008). The lack of physical contact generates a series of behavioral and physiological reactions that affect emotional reactivity of adult rats (Weiss et al, 2004).…”

Effects of cocaine on aggression and associated central ERα and oxytocin expression in ovariectomized and intact mandarin voles

“…However, previous work has paid less attention to other behavioral parameters. As social interaction encompasses different behavioral components with different functions and neurochemical circuits (Varlinskaya & Spear 2008), the effects of ovarian hormone on cocaine-induced social behavior and aggressive behavior requires further investigation.…”