Department of Psychology, Personality Psychology and Assessment, University of Marburg, Marburg, Germany.
Department of Psychology, Clinical Psychology and Psychotherapy, University of Giessen, Giessen, Germany.
Cereb Cortex. 2019 Feb 1;29(2):701-715. doi: 10.1093/cercor/bhx353.
Human functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) studies, as well as animal studies, indicate that the amygdala and frontomedial brain regions are critically involved in conditioned fear and that frontomedial oscillations in the theta range (4-8 Hz) may support communication between these brain regions. However, few studies have used a multimodal approach to probe interactions among these key regions in humans. Here, our goal was to bridge the gap between prior human fMRI, EEG, and animal findings. Using simultaneous EEG-fMRI recordings 24 h after fear conditioning and extinction, conditioned stimuli presented (CS+E, CS-E) and not presented during extinction (CS+N, CS-N) were compared to identify effects specific to extinction versus fear recall. Differential (CS+ vs. CS-) electrodermal, frontomedial theta (EEG) and amygdala responses (fMRI) were reduced for extinguished versus nonextinguished stimuli. Importantly, effects on theta power covaried with effects on amygdala activation. Fear and extinction recall as indicated by theta explained 60% of the variance for the analogous effect in the right amygdala. Our findings show for the first time the interplay of amygdala and frontomedial theta activity during fear and extinction recall in humans and provide insight into neural circuits consistently linked with top-down amygdala modulation in rodents.
人类功能磁共振成像（fMRI）和脑电图（EEG）研究以及动物研究表明，杏仁核和前额叶脑区在条件性恐惧中起着关键作用，而θ频段（4-8Hz）的前额叶振荡可能支持这些脑区之间的通讯。然而，很少有研究采用多模态方法来探测人类这些关键区域之间的相互作用。在这里，我们的目标是弥合先前人类 fMRI、EEG 和动物研究之间的差距。使用恐惧条件作用和消退后 24 小时的同步 EEG-fMRI 记录，将条件刺激呈现（CS+E、CS-E）和消退期间不呈现的条件刺激（CS+N、CS-N）进行比较，以确定特定于消退与恐惧回忆的影响。对于已消退和未消退的刺激，差异（CS+与 CS-）皮肤电反应、前额叶θ（EEG）和杏仁核反应（fMRI）均降低。重要的是，θ功率的影响与杏仁核激活的影响相关。θ 表示的恐惧和消退回忆解释了右侧杏仁核类似效应的 60%的方差。我们的研究结果首次显示了人类在恐惧和消退回忆期间杏仁核和前额叶θ活动的相互作用，并为与啮齿动物中自上而下的杏仁核调节一致的神经回路提供了深入的了解。
