The formation and extinction of fear memories represent two forms of learning that each engage the hippocampus and amygdala. How cell populations in these areas contribute to fear relapse, however, remains unclear. Here, we demonstrate that, in mice, cells active during fear conditioning in the dentate gyrus of hippocampus and basolateral amygdala exhibit decreased activity during extinction and are re-engaged after fear reinstatement. In vivo calcium imaging reveals that reinstatement drives population dynamics in the basolateral amygdala to revert to a network state similar to the state present during fear conditioning. Finally, we find that optogenetic inactivation of neuronal ensembles active during fear conditioning in either the hippocampus or amygdala is sufficient to disrupt fear expression after reinstatement. These results suggest that fear reinstatement triggers a partial re-emergence of the original fear memory representation, providing new insight into the neural substrates of fear relapse.

中文翻译：

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在上下文恐惧复发后，海马和杏仁核恐惧记忆标志重新出现

恐惧记忆的形成和消亡代表两种学习形式，每种学习形式都与海马和杏仁核有关。然而，这些区域的细胞数量如何导致恐惧复发尚不清楚。在这里，我们证明，在小鼠中，在恐惧条件下在海马齿状回和基底外侧杏仁核中活跃的细胞在灭绝过程中表现出降低的活性，并在恐惧恢复后重新参与。体内钙成像显示，恢复活动可驱动基底外侧杏仁核的种群动态，使其恢复为类似于恐惧调节过程中存在的网络状态。最后，我们发现在海马或杏仁核恐惧调节过程中活跃的神经元集成的光遗传学失活足以破坏恢复后的恐惧表达。