Department of Psychiatry, University of British Columbia, Canada.
Behav Brain Res. 2013 Sep 1;252:222-9. doi: 10.1016/j.bbr.2013.06.007. Epub 2013 Jun 10.
The ability to update and modify previously learned behavioral responses in a changing environment is essential for successful utilization of promising opportunities and for coping with adverse events. Valid models of cognitive flexibility that contribute to behavioral flexibility include set-shifting and reversal learning. One immediate effect of acute stress is the selective impairment of performance on higher-order cognitive control tasks mediated by the medial prefrontal cortex (mPFC) but not the hippocampus. Previous studies show that the mPFC is required for set-shifting but not for reversal learning, therefore the aim of the present experiment is to assess whether exposure to acute stress (15 min of mild tail-pinch stress) given immediately before testing on either a set-shifting or reversal learning tasks would impair performance selectively on the set-shifting task. An automated operant chamber-based task, confirmed that exposure to acute stress significantly disrupts set-shifting but has no effect on reversal learning. Rats exposed to an acute stressor require significantly more trials to reach criterion and make significantly more perseverative errors. Thus, these data reveal that an immediate effect of acute stress is to impair mPFC-dependent cognition selectively by disrupting the ability to inhibit the use of a previously relevant cognitive strategy.
在不断变化的环境中更新和修改先前习得的行为反应的能力对于成功利用有前途的机会和应对不利事件至关重要。有助于行为灵活性的认知灵活性的有效模型包括定势转移和反转学习。急性应激的一个直接影响是选择性地损害由内侧前额叶皮层（mPFC）介导但不是海马体介导的高阶认知控制任务的表现。先前的研究表明，mPFC 是定势转移所必需的，但不是反转学习所必需的，因此本实验的目的是评估在进行定势转移或反转学习任务之前立即接受急性应激（15 分钟轻度尾巴捏应激）是否会选择性地损害定势转移任务的表现。基于自动操作室的任务证实，暴露于急性应激会显著破坏定势转移，但对反转学习没有影响。暴露于急性应激源的大鼠需要更多的试验才能达到标准，并犯更多的持续错误。因此，这些数据表明，急性应激的即时影响是通过破坏抑制先前相关认知策略的能力来选择性地损害 mPFC 依赖性认知。
