Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, 92521, USA.
Nat Commun. 2020 Mar 13;11(1):1382. doi: 10.1038/s41467-020-15121-2.
In contextual fear conditioning, experimental subjects learn to associate a neutral context with an aversive stimulus and display fear responses to a context that predicts danger. Although the hippocampal-amygdala pathway has been implicated in the retrieval of contextual fear memory, the mechanism by which fear memory is encoded in this circuit has not been investigated. Here, we show that activity in the ventral CA1 (vCA1) hippocampal projections to the basal amygdala (BA), paired with aversive stimuli, contributes to encoding conditioned fear memory. Contextual fear conditioning induced selective strengthening of a subset of vCA1-BA synapses, which was prevented under anisomycin-induced retrograde amnesia. Moreover, a subpopulation of BA neurons receives stronger monosynaptic inputs from context-responding vCA1 neurons, whose activity was required for contextual fear learning and synaptic potentiation in the vCA1-BA pathway. Our study suggests that synaptic strengthening of vCA1 inputs conveying contextual information to a subset of BA neurons contributes to encoding adaptive fear memory for the threat-predictive context.
在情境恐惧条件反射中，实验对象学会将中性环境与厌恶刺激联系起来，并对预测危险的环境表现出恐惧反应。尽管海马-杏仁核通路已被牵涉到情境恐惧记忆的提取中，但这个回路中恐惧记忆是如何被编码的机制尚未被研究。在这里，我们表明，与厌恶刺激配对的腹侧 CA1（vCA1）海马投射到基底杏仁核（BA）的活动有助于编码条件性恐惧记忆。情境恐惧条件反射诱导了 vCA1-BA 突触的子集的选择性增强，而在anisomycin 诱导的逆行性遗忘下，这种增强被阻止了。此外，BA 神经元的一个亚群从对上下文作出反应的 vCA1 神经元接收更强的单突触输入，而 vCA1-BA 通路中的活动对于情境恐惧学习和突触增强是必需的。我们的研究表明，向 BA 神经元的子集传递上下文信息的 vCA1 输入的突触增强有助于对威胁预测环境的适应性恐惧记忆进行编码。
