Schwabe Lars, Oitzl Melly S, Richter Steffen, Schächinger Hartmut
Department of Clinical Physiology, Institute of Psychobiology, University of Trier, Johanniterstrasse 15, 52490 Trier, Germany.
Psychoneuroendocrinology. 2009 Apr;34(3):358-66. doi: 10.1016/j.psyneuen.2008.09.018. Epub 2008 Nov 5.
Glucocorticoids (GCs) are known to influence learning and memory processes. While most studies focus on the effects of GCs on the performance within a single memory system, we asked whether GCs modulate also the transition between hippocampus-dependent spatial and caudate nucleus-dependent stimulus-response memory systems. Eighty-four young healthy women received a placebo, 5 or 30 mg hydrocortisone orally. One hour later, participants were asked to locate a win-card in a 3D model of a room. The card could be located via two strategies: spatial (multiple distal cues) and stimulus-response (a single proximal cue). Relocation of the proximal cue after 12 trials revealed the strategy, number of trials to learning criterion the performance. As expected, more trials were needed to acquire the task with hydrocortisone. Remarkably, hydrocortisone switched the use of learning strategies towards more spatial learning (dose-dependently: placebo 4% < 5 mg 21%< 30 mg 32%), independent of autonomic and subjective arousal. The learning curves of spatial and stimulus-response learners were comparable. Our results demonstrate that exogenous GCs prior to learning affect the performance within a memory system and also coordinate the use of multiple memory systems. Taking into account this dual action of GCs will contribute to a better understanding of stress (hormone) effects on learning and memory.
已知糖皮质激素（GCs）会影响学习和记忆过程。虽然大多数研究聚焦于GCs对单一记忆系统内表现的影响，但我们探究了GCs是否也会调节海马体依赖的空间记忆系统和尾状核依赖的刺激-反应记忆系统之间的转换。84名年轻健康女性口服了安慰剂、5毫克或30毫克氢化可的松。一小时后，参与者被要求在一个房间的三维模型中找到一张中奖卡片。可以通过两种策略找到这张卡片：空间策略（多个远端线索）和刺激-反应策略（单个近端线索）。在12次试验后重新放置近端线索以揭示策略，达到学习标准所需的试验次数即表现。正如预期的那样，服用氢化可的松后完成任务需要更多试验。值得注意的是，氢化可的松使学习策略的使用转向更多的空间学习（剂量依赖性：安慰剂4% < 5毫克21% < 30毫克32%），且与自主神经和主观唤醒无关。空间学习者和刺激-反应学习者的学习曲线具有可比性。我们的结果表明，学习前的外源性GCs会影响记忆系统内的表现，还会协调多个记忆系统的使用。考虑到GCs的这种双重作用将有助于更好地理解压力（激素）对学习和记忆的影响。
