Gisquet-Verrier Pascale, Botreau Fanny, Venero Cesar, Sandi Carmen
Laboratoire de Neurobiologie de l'Apprentissage et de la Mémoire et de la Communication, UMR CNRS 8620, Université Paris-Sud, 91405 Orsay cedex, France.
Psychoneuroendocrinology. 2004 May;29(4):529-56. doi: 10.1016/s0306-4530(03)00085-4.
Memory retrieval can be facilitated by pretest exposure to cues associated with the original training. The present series of experiments was aimed at investigating whether the effectiveness of the retrieval cues might be due to their emotional value and thus be associated to a particular pattern of activation of stress systems. Therefore, the effects of exposing rats to different cueing conditions were investigated both on retention performance and on the level of different stress hormones (ACTH, corticosterone and glucose; the latter as an indirect index of adrenergic/sympathetic nervous system activation). Rats trained in a brightness avoidance discrimination task exhibited an enhancement of the retention performance following exposure to the light discriminative stimulus when delivered 1-day after training and not after 21 days, while exposure to contextual cues led to opposite effects on the retention performance, confirming our previous results. Analyses of the level of stress hormones at the time of testing indicated that when the retrieval cues were effective at the behavioral level, cued rats exhibited higher ACTH plasmatic levels than controls, but did not differ in their glucose or corticosterone levels. Further experiments showed that one day after training, both ACTH and corticosterone levels were elevated in light-cued rats if hormone samples were taken 15 min after cueing. These results show that exposure to an effective retrieval cue is accompanied by the activation of the hypothalamus-pituitary-adrenal axis. The possible involvement of the Corticotropin Releasing Factor at the level of the hypothalamus and amygdala (particularly the central nucleus) on the facilitating effect on retention performance following exposure to aversive training-associated cues is discussed. The present results strengthen the notion that emotion can interact with retrieval processes.
预测试时接触与原始训练相关的线索可以促进记忆提取。本系列实验旨在研究提取线索的有效性是否可能归因于其情感价值，从而与应激系统的特定激活模式相关联。因此，研究了让大鼠暴露于不同线索条件下对记忆保持表现以及不同应激激素（促肾上腺皮质激素、皮质酮和葡萄糖；后者作为肾上腺素能/交感神经系统激活的间接指标）水平的影响。在亮度回避辨别任务中接受训练的大鼠，在训练后1天而非21天后接受光辨别刺激时，记忆保持表现得到增强，而接触情境线索则对记忆保持表现产生相反影响，这证实了我们之前的结果。测试时对应激激素水平的分析表明，当提取线索在行为水平上有效时，接受线索提示的大鼠血浆促肾上腺皮质激素水平高于对照组，但葡萄糖或皮质酮水平并无差异。进一步的实验表明，训练后一天，如果在提示后15分钟采集激素样本，光提示大鼠的促肾上腺皮质激素和皮质酮水平均会升高。这些结果表明，接触有效的提取线索会伴随着下丘脑 - 垂体 - 肾上腺轴的激活。讨论了促肾上腺皮质激素释放因子在下丘脑和杏仁核（特别是中央核）水平上对暴露于厌恶训练相关线索后对记忆保持表现的促进作用可能产生的影响。目前的结果强化了情绪可与提取过程相互作用这一观点。
