Adolescent social instability stress increases aggression in a food competition task in adult male Long-Evans rats.
Adolescent social instability stress (SS; daily 1 hr isolation + new cage partners postnatal days 30-45; thereafter with original cage partner, also in the SS condition) and control (CTL) rats competed for access to a preferred food in five sessions against their cage partner. In the first session, SS pairs displayed more aggression (face whacks, p = .02; rear attacks, p = .03), were less likely to relinquish access to the food voluntarily (p = .03), spent more time at the feeder than CTL pairs (p = .06), but did not differ in latency to access the feeder (p = .41). Pairs were considered in dominant-submissive relationships (DSR) if one rat spent significantly more time at the feeder than the other; 8 of 12 SS and 8 of 12 CTL pairs displayed DSRs (remaining: no-DSR). Aggression increased from the 1st to 5th session (p < .001), was greater in no-DSR than DSR pairs (p = .04; consistent with the proposed function of DSRs to be the reduction of aggression in groups), and was higher in SS than CTL pairs (p = .05). Because the increased aggression of SS compared with CTL pairs did not result in a significant increase in their time at the feeder, the increased aggression may be considered maladaptive, and may reflect an increased motivation for food reward. These results add to evidence that SS in adolescence modifies the adult social repertoire of rats and highlight the importance of adolescent social experiences for adult behavior.
['Cumming|Mark J|MJ|', 'Thompson|Madison A|MA|', 'McCormick|Cheryl M|CM|']
D000367:Age Factors D000374:Aggression D000818:Animals D001522:Behavior, Animal D003163:Competitive Behavior D004291:Dominance-Subordination D005502:Food D008297:Male D011897:Random Allocation D051381:Rats D020318:Rats, Long-Evans D013315:Stress, Psychological
adolescence social stress aggression rats dominance early experiences