Learning to associate certain contexts with threat and adapting to changing environmental contingencies by learning that such contexts are no longer associated with threat are both crucial for survival. Research over the last few decades has made considerable progress in determining the brain areas involved in the encoding, retrieval and extinction of contextual fear. These studies have identified the hippocampus and amygdala, along with the prefrontal cortex and other inter-connected brain areas, as key players in contextual fear processing. In contrast to the neural circuit basis of contextual fear, the neurochemical mechanisms involved in its regulation remain poorly understood. Dopamine is well known for its role in appetitive learning but this neurotransmitter is also important for other types of learning, including spatial and aversive memory processing. Dopamine is ideally positioned to regulate contextual fear given that the areas involved receive dopamine input and express dopamine receptors. Moreover, neuronal activity, functional connectivity and synaptic plasticity in this neural circuitry are modulated by dopamine receptor signalling. Here, we review the evidence indicating that dopamine regulates various contextual fear processes, along with the more recent studies that have begun to elucidate the brain areas and neurophysiological mechanisms involved. From a fundamental research perspective, understanding how dopamine regulates contextual fear will lead to novel insights on the neurochemical modulation of neural circuit function underlying memory processing. This research may also have translational relevance given that contextual fear conditioning and extinction also provide useful preclinical models of certain aspects of anxiety-related disorders and their treatment.

中文翻译：

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情境恐惧和相关神经回路功能的多巴胺调节

学会将某些环境与威胁联系起来，并通过了解这些环境不再与威胁相关联来适应不断变化的环境突发事件，这对生存都至关重要。过去几十年的研究在确定与情境恐惧的编码、检索和消除相关的大脑区域方面取得了相当大的进展。这些研究已经确定海马体和杏仁核，以及前额叶皮层和其他相互连接的大脑区域，是情境恐惧处理的关键参与者。与情境恐惧的神经回路基础相反，对其调节所涉及的神经化学机制仍知之甚少。多巴胺以其在食欲学习中的作用而闻名，但这种神经递质对于其他类型的学习也很重要，包括空间和厌恶记忆处理。鉴于所涉及的区域接收多巴胺输入并表达多巴胺受体，多巴胺非常适合调节情境恐惧。此外，该神经回路中的神经元活动、功能连接和突触可塑性受多巴胺受体信号传导的调节。在这里，我们回顾了表明多巴胺调节各种情境恐惧过程的证据，以及最近开始阐明所涉及的大脑区域和神经生理机制的研究。从基础研究的角度来看，了解多巴胺如何调节情境恐惧将导致对记忆处理背后的神经回路功能的神经化学调节的新见解。