Vanelzakker Michael B, Zoladz Phillip R, Thompson Vanessa M, Park Collin R, Halonen Joshua D, Spencer Robert L, Diamond David M
Department of Psychology and Neuroscience, University of Colorado Boulder, CO, USA.
Front Behav Neurosci. 2011 Jun 24;5:30. doi: 10.3389/fnbeh.2011.00030. eCollection 2011.
We have studied the influence of pre-training psychological stress on the expression of c-fos mRNA following long-term spatial memory retrieval. Rats were trained to learn the location of a hidden escape platform in the radial-arm water maze, and then their memory for the platform location was assessed 24 h later. Rat brains were extracted 30 min after the 24-h memory test trial for analysis of c-fos mRNA. Four groups were tested: (1) Rats given standard training (Standard); (2) Rats given cat exposure (Predator Stress) 30 min prior to training (Pre-Training Stress); (3) Rats given water exposure only (Water Yoked); and (4) Rats given no water exposure (Home Cage). The Standard trained group exhibited excellent 24 h memory which was accompanied by increased c-fos mRNA in the dorsal hippocampus and basolateral amygdala (BLA). The Water Yoked group exhibited no increase in c-fos mRNA in any brain region. Rats in the Pre-Training Stress group were classified into two subgroups: good and bad memory performers. Neither of the two Pre-Training Stress subgroups exhibited a significant change in c-fos mRNA expression in the dorsal hippocampus or BLA. Instead, stressed rats with good memory exhibited significantly greater c-fos mRNA expression in the dorsolateral striatum (DLS) compared to stressed rats with bad memory. This finding suggests that stressed rats with good memory used their DLS to generate a non-spatial (cue-based) strategy to learn and subsequently retrieve the memory of the platform location. Collectively, these findings provide evidence at a molecular level for the involvement of the hippocampus and BLA in the retrieval of spatial memory and contribute novel observations on the influence of pre-training stress in activating the DLS in response to long-term memory retrieval.
我们研究了训练前心理应激对长期空间记忆检索后c-fos mRNA表达的影响。将大鼠训练以学习放射状臂水迷宫中隐藏逃生平台的位置，然后在24小时后评估它们对平台位置的记忆。在24小时记忆测试试验后30分钟提取大鼠大脑，用于分析c-fos mRNA。测试了四组：(1) 接受标准训练的大鼠（标准组）；(2) 在训练前30分钟接受猫暴露的大鼠（捕食者应激组）（训练前应激组）；(3) 仅接受水暴露的大鼠（水匹配组）；以及(4) 未接受水暴露的大鼠（饲养笼组）。标准训练组表现出良好的24小时记忆，同时背侧海马体和基底外侧杏仁核（BLA）中的c-fos mRNA增加。水匹配组在任何脑区的c-fos mRNA均未增加。训练前应激组的大鼠分为两个亚组：记忆良好和记忆不佳的表现者。训练前应激组的两个亚组在背侧海马体或BLA中的c-fos mRNA表达均未出现显著变化。相反，与记忆不佳的应激大鼠相比，记忆良好的应激大鼠在背外侧纹状体（DLS）中表现出显著更高的c-fos mRNA表达。这一发现表明，记忆良好的应激大鼠利用其DLS生成一种非空间（基于线索）策略来学习并随后检索平台位置的记忆。总的来说，这些发现为海马体和BLA参与空间记忆检索提供了分子水平的证据，并为训练前应激在激活DLS以响应长期记忆检索方面的影响提供了新的观察结果。
