Snyder Kevin, Barry Mark, Plona Zachary, Ho Andrew, Zhang Xiao-Yan, Valentino Rita J
The University of Pennsylvania, Philadelphia, PA 19104, USA.
The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Behav Brain Res. 2015 Jun 1;286:175-83. doi: 10.1016/j.bbr.2015.02.047. Epub 2015 Mar 5.
The age of stressor exposure can determine its neurobehavioral impact. For example, exposure of adolescent male rats to resident-intruder stress impairs cognitive flexibility in adulthood. The current study examined the impact of this stressor in female rats. Rats were exposed to resident-intruder stress during early adolescence (EA), mid-adolescence (MA) or adulthood (Adult). They were tested in an operant strategy-shifting task for side discrimination (SD), reversal learning (REV) and strategy set-shifting (SHIFT) the following week. Performance varied with age, stress and coping style. MA and EA rats performed SD and SHIFT better than other ages, respectively. Social stress impaired performance in rats depending on their coping strategy as determined by a short (SL) or long (LL) latency to become subordinate. SL rats were impaired in SD and REV, whereas EA-LL rats were impaired in SHIFT. These impairing effects of female adolescent stress did not endure into adulthood. Strategy set-shifting performance for female adolescents was positively correlated with medial prefrontal cortex (mPFC) activation as indicated by c-fos expression suggesting that this region is engaged during task performance. This contrasts with the inverse relationship between these indices reported for male adolescent rats. Together, the results demonstrate that social stress produces cognitive impairments for female rats that depend on age and coping style but unlike males, the impairing effects of female adolescent social stress are immediate and do not endure into adulthood. Sex differences in the impact of adolescent social stress on cognition may reflect differences in mPFC engagement during the task.
应激源暴露的年龄可以决定其对神经行为的影响。例如，青春期雄性大鼠遭受住-侵者应激会损害其成年后的认知灵活性。当前的研究考察了这种应激源对雌性大鼠的影响。大鼠在青春期早期（EA）、青春期中期（MA）或成年期（Adult）遭受住-侵者应激。接下来的一周，它们在一项操作性策略转换任务中接受侧别辨别（SD）、逆向学习（REV）和策略集转换（SHIFT）测试。表现因年龄、应激和应对方式而异。MA组和EA组大鼠在SD和SHIFT任务中的表现分别优于其他年龄段的大鼠。社会应激会损害大鼠的表现，这取决于它们的应对策略，应对策略由成为从属地位的短（SL）或长（LL）潜伏期来确定。SL组大鼠在SD和REV任务中表现受损，而EA-LL组大鼠在SHIFT任务中表现受损。雌性青春期应激的这些损害作用不会持续到成年期。雌性青少年的策略集转换表现与内侧前额叶皮质（mPFC）激活呈正相关，如c-fos表达所示，表明该区域在任务执行过程中被激活。这与雄性青少年大鼠报道的这些指标之间的反向关系形成对比。总之，结果表明社会应激会给雌性大鼠带来认知损害，这种损害取决于年龄和应对方式，但与雄性不同的是，雌性青春期社会应激的损害作用是即时的，不会持续到成年期。青春期社会应激对认知影响的性别差异可能反映了任务过程中mPFC参与情况的差异。
