Mechanisms for phase shift of reactivated memory

记忆提取启动了两个相反的过程：记忆重新巩固和消退。记忆再巩固维持或增强恐惧记忆，而记忆消退则削弱恐惧记忆。在这项研究中，我们试图通过分析转录因子CREB、ERK的激活以及海马、杏仁核和mPFC中蛋白酶体依赖的蛋白降解来了解决定记忆提取后命运的机制。我们鉴定了再巩固神经元和消亡神经元，它们分别在再巩固和消退阶段表现出不同的生化特征。更重要的是，在消失期，再巩固神经元被灭活，而消亡神经元激活了ERK信号通路。根据这些观察，我们得出结论，在记忆提取后从重新巩固到消失的阶段中，海马体起着关键作用。

Memory retrieval initiates two opposite processes; memory reconsolidation and extinction. Memory reconsolidation maintains or enhances fear memory, whereas memory extinction weakens fear memory. In this study, we tried to understand mechanisms by which the fate of memory is determined after retrieval by analyzing activation of transcription factor CREB, ERK and proteasome-dependent protein degradation in the hippocampus, amygdala and mPFC. We identified reconsolidation neurons and extinction neurons that display distinct biochemical features in reconsolidation and extinction phases, respectively. More importantly, in the extinction phase, reconsolidation neurons were inactivated while extinction neurons activated ERK signaling pathway in the hippocampus. From these observations, we concluded that hippocampus plays key roles in the phase shift from reconsolidation to extinction following memory retrieval.