Cumming Mark J, Thompson Madison A, McCormick Cheryl M
Centre for Neuroscience, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, Canada, L2S 3A1.
Dev Psychobiol. 2014 Nov;56(7):1575-88. doi: 10.1002/dev.21252. Epub 2014 Sep 1.
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.
青少年社会不稳定应激(SS;产后第30 - 45天每天1小时隔离 + 新笼伴;此后与原笼伴在一起,也处于SS条件下)和对照(CTL)大鼠与它们的笼伴进行了五轮竞争,以获取喜爱的食物。在第一轮中,SS组对表现出更多的攻击性(打脸,p = 0.02;后攻,p = 0.03),更不愿意自愿放弃获取食物的机会(p = 0.03),在喂食器处花费的时间比CTL组对更多(p = 0.06),但在获取喂食器的潜伏期方面没有差异(p = 0.41)。如果一只大鼠在喂食器处花费的时间明显多于另一只,则这对大鼠被认为处于支配 - 顺从关系(DSR);12对SS组中有8对和12对CTL组中有8对表现出DSR(其余:无DSR)。攻击性从第1轮增加到第5轮(p < 0.001),无DSR组对的攻击性大于DSR组对(p = 0.04;与DSR在群体中减少攻击性的拟议功能一致),且SS组对比CTL组对更高(p = 0.05)。由于与CTL组对相比,SS组对攻击性的增加并未导致它们在喂食器处停留时间的显著增加,因此增加的攻击性可能被认为是适应不良的,并且可能反映了对食物奖励的动机增加。这些结果进一步证明了青春期的SS会改变成年大鼠的社会行为模式,并突出了青少年社会经历对成年行为的重要性。