Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular y Celular, FCEyN, Universidad de Buenos Aires, IFIBYNE-CONICET, Argentina.
Neuroscience. 2013 Aug 29;246:397-408. doi: 10.1016/j.neuroscience.2013.04.033. Epub 2013 Apr 24.
When a consolidated memory is reactivated, it can become labile and prone to enhancement or disruption, a process known as reconsolidation. The reconsolidation hypothesis has challenged the traditional view that memories after consolidation are fixed and unchangeable. Recent studies suggest that the mechanisms mediating memory retrieval and the mechanisms that underlie the behavioral expression of memory can be dissociated, offering a new promise for the understanding of human memory persistence. Although reconsolidation studies typically use amnesic agents, it has also been shown that memory can be enhanced by pharmacological agents and real-life events during reconsolidation. Recently, we demonstrated that a mild stressor, cold pressor stress (CPS), can enhance human declarative memory during reconsolidation in a cued-recall test. Here we evaluate whether the recollection of 7- or 20-day-old long-term memories can be improved by exposure to two different neuromodulators: a mild stressor and glucose during reconsolidation. As expected, poor and very poor memory performance was found at the time of memory reactivation (days 6 and 20 after training). CPS during reconsolidation improved the long-term expression of a declarative memory 6 -but not 20-days after training. However, the administration of an oral source of glucose (juice), but not a diet juice, can enhance memory during reconsolidation even 20 days after training. Interestingly, when a recognition test was applied instead of a cued-recall test, memory performance was still robust at both 1 and 3 weeks after training. Here we show that the period in which this memory can be reactivated and become labile largely exceeds the period in which that memory is recalled, proving evidence that conscious access is not needed for reconsolidation. Present results are consistent with dissociation between the mechanisms mediating memory labilization and the mechanisms that underlie the behavioral expression of memory.
当一个整合后的记忆被重新激活时，它可能变得不稳定，容易受到增强或干扰，这个过程被称为再巩固。再巩固假说挑战了传统的观点，即巩固后的记忆是固定的、不可改变的。最近的研究表明，介导记忆检索的机制和记忆行为表达的机制可以分离，为理解人类记忆的持久性提供了新的希望。尽管再巩固研究通常使用健忘剂，但也有研究表明，在再巩固过程中，药物和现实生活事件可以增强记忆。最近，我们证明在提示回忆测试中，轻度压力源冷水加压应激（CPS）可以在再巩固过程中增强人类陈述性记忆。在这里，我们评估两种不同的神经调节剂：在再巩固过程中暴露于轻度压力源和葡萄糖是否可以改善 7 天或 20 天的长期记忆的回忆。正如预期的那样，在记忆重新激活时（训练后 6 天和 20 天）发现了较差和非常差的记忆表现。在再巩固过程中施加 CPS 可以改善陈述性记忆的长期表达，但仅在训练后 6 天，而不是 20 天。然而，给予口服葡萄糖源（果汁）而不是饮食果汁可以增强再巩固过程中的记忆，即使在训练后 20 天也是如此。有趣的是，当应用识别测试而不是提示回忆测试时，在训练后 1 周和 3 周时，记忆表现仍然很稳定。在这里，我们证明了这段记忆可以被重新激活并变得不稳定的时间远远超过了那段记忆被回忆的时间，证明了无意识访问对于再巩固并不需要。目前的结果与介导记忆不稳定的机制和记忆行为表达的机制之间的分离是一致的。
