International School, Jinan University, Guangzhou 510632, China.
Department of Public Health and Preventive Medicine, School of Basic Medicine, Jinan University, Guangzhou 510632, China; Division of Medical Psychology and Behavior Science, School of Basic Medicine, Jinan University, Guangzhou 510632, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou 510515, China.
Neuroimage. 2021 Feb 15;227:117686. doi: 10.1016/j.neuroimage.2020.117686. Epub 2020 Dec 29.
Processing of fear is of crucial importance for human survival and it can generally occur at explicit and implicit conditions. It is worth noting that explicit and implicit fear processing produces different behavioral and neurophysiological outcomes. The present study capitalizes on the Activation Likelihood Estimation (ALE) method of meta-analysis to identify: (a) the "core" network of fear processing in healthy individuals; (b) common and specific neural activations associated with explicit and implicit processing of fear. Following PRISMA guidelines, a total of 92 fMRI and PET studies were included in the meta-analysis. The overall analysis show that the core fear network comprises the amygdala, pulvinar, and fronto-occipital regions. Both implicit and explicit fear processing activated amygdala, declive, fusiform gyrus, and middle frontal gyrus, suggesting that these two types of fear processing share a common neural substrate. Explicit fear processing elicited more activations at the pulvinar and parahippocampal gyrus, suggesting visual attention/orientation and contextual association play important roles during explicit fear processing. In contrast, implicit fear processing elicited more activations at the cerebellum-amygdala-cortical pathway, indicating an 'alarm' system underlying implicit fear processing. These findings have shed light on the neural mechanism underlying fear processing at different levels of awareness.
恐惧的处理对人类的生存至关重要，它通常可以在显式和隐式条件下发生。值得注意的是，显式和隐式的恐惧处理会产生不同的行为和神经生理结果。本研究利用元分析的激活似然估计（ALE）方法来确定：（a）健康个体恐惧处理的“核心”网络；（b）与显式和隐式恐惧处理相关的共同和特定的神经激活。根据 PRISMA 指南，共有 92 项 fMRI 和 PET 研究被纳入元分析。总体分析表明，恐惧的核心网络包括杏仁核、丘脑枕和额枕区域。隐式和显式恐惧处理都激活了杏仁核、下丘、梭状回和额中回，表明这两种类型的恐惧处理共享共同的神经基础。显式恐惧处理在丘脑枕和海马旁回引起更多的激活，表明视觉注意/定向和上下文关联在显式恐惧处理中起着重要作用。相比之下，隐式恐惧处理在小脑-杏仁核-皮质通路引起更多的激活，表明隐式恐惧处理有一个“警报”系统。这些发现揭示了不同意识水平下恐惧处理的神经机制。
