University of Trier, Germany.
J Cogn Neurosci. 2010 Jul;22(7):1362-72. doi: 10.1162/jocn.2009.21278.
Stress and corticosteroid hormones are known to affect learning and memory processes. In this study, we examined whether stress and corticosteroids are capable of facilitating the switch between multiple memory systems in mice. For this purpose, we designed a task that allowed measurement of nucleus caudate-based stimulus-response and hippocampus-based spatial learning strategies. Naive mice used spatial strategies to locate an exit hole on a circular hole board at a fixed location flagged by a proximal stimulus. When the mice were either stressed or administered corticosterone before the task, 30-50% of the mice switched to a stimulus-response strategy. This switch between learning strategies was accompanied by a rescue of performance, whereas performance declined in the stressed mice that kept using the spatial strategy. Pretreatment with a mineralocorticoid receptor antagonist prevented the switch toward the stimulus-response strategy but led to deterioration of hippocampus-dependent performance. These findings (i) show that corticosteroids promote the transition from spatial to stimulus-response memory systems, (ii) provide evidence that the mineralocorticoid receptor underlies this corticosteroid-mediated switch, and (iii) suggest that a stress-induced switch from hippocampus-based to nucleus caudate-based memory systems can rescue performance.
压力和皮质甾类激素已知会影响学习和记忆过程。在这项研究中，我们研究了压力和皮质甾类激素是否能够促进小鼠中多个记忆系统之间的转换。为此，我们设计了一项任务，该任务允许测量基于尾状核的刺激-反应和基于海马体的空间学习策略。在圆形孔板上，未经过训练的小鼠使用空间策略在固定位置的近端刺激物标记下找到出口孔。当小鼠在任务之前承受压力或接受皮质酮处理时，30-50％的小鼠转换为刺激-反应策略。这种学习策略之间的转换伴随着表现的恢复，而持续使用空间策略的应激小鼠的表现则下降。预先用盐皮质激素受体拮抗剂处理可防止向刺激-反应策略的转变，但会导致对海马体依赖性表现的恶化。这些发现（i）表明皮质甾类激素促进了从空间到刺激-反应记忆系统的转变，（ii）提供了证据表明，矿物质皮质激素受体是这种皮质甾类激素介导的转变的基础，以及（iii）表明应激引起的从基于海马体的记忆系统到基于尾状核的记忆系统的转变可以恢复表现。
