A Switch from Cycloheximide-Resistant Consolidated Memory to Cycloheximide-Sensitive Reconsolidation and Extinction in Drosophila
A Switch from Cycloheximide-Resistant Consolidated Memory to Cycloheximide-Sensitive Reconsolidation and Extinction in Drosophila
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DOI：
10.1523/jneurosci.3789-08.2009
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发表时间：
2009-02-18
影响因子：
5.3
通讯作者：
Mery, Frederic
中科院分区：
文献类型：
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作者：
Lagasse, Fabrice;Devaud, Jean-Marc;Mery, Frederic
人们普遍认为，在学习之后，记忆随着时间的推移而稳定，并通过巩固过程整合到长期记忆（LTM）中，这取决于从头蛋白质合成。此外，对几个物种的研究表明，已经稳定的LTM的重新激活可以使这种记忆不稳定，然后重新稳定（称为重新巩固的过程）或抑制它（灭绝）。然而，这两个过程的身份及其相互作用与巩固仍在辩论中。关于记忆稳定性，果蝇提供了一个惊人的例外，因为在这个物种中，LTM不是唯一稳定的记忆形式。在特定的学习条件下，抗麻醉记忆（ARM）可以通过未知的过程形成，但对环己酰亚胺（一种经典的蛋白质合成抑制剂，会损害LTM）具有抗性。在这里，我们利用这种二分法来询问ARM和LTM是否可以被消灭和/或重新巩固。我们还研究了果蝇是否存在两种形式的记忆消退和重新巩固，至于记忆稳定。我们发现，无论是重新巩固或灭绝后，可以诱导果蝇的嗅觉条件反射，这取决于在其他物种的重新激活的数量。此外，关于放线菌酮的作用，稳定的ARM/LTM二分法不适用于消退和再巩固。阻断蛋白质合成干扰这两个过程，无论初始稳定是否敏感（LTM）或不（ARM）放线菌酮。因此，这些结果表明，果蝇是一个有用的模型来解决这些问题，并重新巩固不一定是一个简单的重复巩固。
It is generally accepted that, after learning, memories stabilize over time and integrate into long-term memory (LTM) through the process of consolidation, which depends on de novo protein synthesis. Besides, studies on several species have shown that reactivation of already stabilized LTM can either make this memory labile and then restabilize it (a process called reconsolidation) or inhibit it (extinction). However, the identity of both processes and their interactions with consolidation are still under debate. Regarding memory stabilization, Drosophila offers a striking exception since, in this species, LTM is not the sole stable form of memory. Under specific learning conditions, anesthesia-resistant memory (ARM) can be formed through processes yet unknown but that are resistant to cycloheximide, a classical protein synthesis inhibitor that impairs LTM. Here, we took advantage of this dichotomy to ask whether both ARM and LTM could be extinguished and/or reconsolidated. We also studied whether two forms of memory extinction and reconsolidation exist in flies, as for memory stabilization. We show that either reconsolidation or extinction can be induced after olfactory conditioning in Drosophila, depending on the number of reactivations as in other species. Furthermore, regarding the effect of cycloheximide, the ARM/LTM dichotomy for stabilization does not apply to extinction and reconsolidation. Blocking protein synthesis interfered with both processes regardless of whether initial stabilization was sensitive (LTM) or not (ARM) to cycloheximide. These results thus show that Drosophila is a useful model to tackle these questions and that reconsolidation is not necessarily a mere repetition of consolidation.