Fear extinction is generally considered a form of new learning that inhibits previously acquired fear memories. Here, by tracking immediate early gene expression in vivo, we found that contextual fear extinction training evoked distinct neural ensembles in mouse retrosplenial cortex (RSC). The optogenetic reactivation of these extinction-activated neurons in the RSC was sufficient to suppress a fear response, while the reactivation of conditioning-activated neurons in the same area promoted a fear response. The generation of such an extinction-memory-related neural ensemble was associated with adult neurogenesis, as abolishing newborn neurons in the adult hippocampus via X-ray irradiation eliminated both the extinction-activated neurons in the RSC and the optogenetic-reactivation-induced suppression of contextual fear memory. Therefore, switching from fear to no fear in response to the same context is modulated by the RSC through an extinction-activated neural ensemble, the generation of which might require adult neurogenesis in the hippocampus.

中文翻译：

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在小鼠后脾皮层中通过不同的神经集成从恐惧转换为无恐惧。

恐惧绝种通常被认为是一种新的学习形式，它可以抑制以前获得的恐惧记忆。在这里，通过跟踪体内的早期早期基因表达，我们发现情境恐惧消灭训练在小鼠脾后皮质（RSC）中引起了独特的神经集合。RSC中这些消光激活的神经元的光遗传学激活足以抑制恐惧反应，而同一区域中条件激活的神经元的重新激活则促进了恐惧反应。这种与灭绝记忆有关的神经集合体的产生与成年神经发生有关，因为通过X射线辐照消除成年海马中的新生神经元消除了RSC中的灭绝激活神经元和光遗传学激活诱导的神经元抑制。上下文恐惧记忆。所以，