Data_Sheet_1_Procedures between training and reactivation influence the destabilization of instrumental sucrose memory.docx

Memory destabilization and reconsolidation is hypothesized to be a fundamental mnemonic process that can underpin memory updating. Instrumental memories have been shown recently to be destabilized following a reactivation session that involves a change in instrumental reward contingency. However, the acquisition and performance of an instrumental response occurs in the presence of the learning of other reward-related memories. This may influence the ability of a given reactivation session to destabilize the previously learned instrumental memory. Here we present a series of experiments in male rats involving an instrumental memory trained on an FR1 schedule over 10 days, and then reactivated in a session that imposed a VR5 schedule of reinforcement. When MK-801 was injected prior to the VR5 reactivation session, it reliably impaired subsequent instrumental performance at test only when the reactivation session occurred 48 h, and not 24 h, after the end of training. The interposition between the end of training and the reactivation session of a context extinction session, an additional VR5 reactivation session, or indeed the simple experience of being handled and injected with vehicle, resulted in MK-801 no longer having an amnestic effect on test performance. While we do not have a clear account for the process and mechanism underpinning this apparent selectivity of the effect of the VR5 session to destabilize the instrumental memory, it does additionally highlight the need for greater understanding of the conditions that facilitate reactivation-induced memory destabilization.

记忆破坏与再巩固（Memory destabilization and reconsolidation）被假设为支撑记忆更新的核心记忆过程。近期研究证实，当工具性记忆（instrumental memory）的激活会话涉及工具性奖赏偶联发生改变时，该记忆可被破坏。然而，工具性反应的习得与表现往往伴随其他奖赏相关记忆的形成，这可能会影响特定激活会话破坏此前习得的工具性记忆的能力。
本研究针对雄性大鼠开展了一系列实验：首先以固定比率1（FR1）强化方案训练10天，使其形成工具性记忆，随后采用可变比率5（VR5）强化方案的激活会话对其进行记忆激活。若在VR5激活会话前注射MK-801，仅当激活会话于训练结束48小时后（而非24小时后）开展时，该药物可显著损伤后续测试中的工具性表现。
若在训练结束与VR5激活会话之间插入环境消退会话、额外的VR5激活会话，或仅进行抓取与溶剂注射的操作，则MK-801不再对测试表现产生遗忘效应。
尽管目前我们尚未明确VR5会话破坏工具性记忆这一选择性效应的具体过程与机制，但本研究确实凸显了深入理解促进激活诱导记忆破坏的条件的必要性。