Cognitives Neurosciences Laboratory, INSERM U960 and DEC-Ecole Normale Supérieure, Paris, France.
Hum Brain Mapp. 2010 Oct;31(10):1469-81. doi: 10.1002/hbm.20953.
Being exposed to fear signals makes us feel threatened and prompts us to prepare an adaptive response. In our previous studies, we suggested that amygdala (AMG) and premotor cortex (PM) play a role in the preparation of the observers' motor response required by the situation. The present experiment aimed at assessing how interindividual differences in alexithymia--a personality trait associated with deficits in emotional reactivity and regulation--influence the neural network associated with the perception of fear. Using fMRI, we scanned 34 healthy subjects while they were passively observing fearful body expressions. Applying a dimensional approach, we performed correlation analyses between fear-related brain areas and alexithymia scores among all participants. Using a categorical approach, we conducted a between-group comparison (13 high vs. 12 low-alexithymia subjects). Our results were threefold. First, the right AMG activity in response to fearful stimuli was negatively correlated with the level of difficulty to identify emotions. Second, PM activity was linked to reduced subjective emotional reactivity. Third, the between-group comparison revealed greater activity in anterior cingulate cortex (ACC) for high than low-alexithymia scorers. Moreover, the relationship between ACC and PM was in opposite direction in individuals with high (negative link) and low (positive link) alexithymia. Therefore, compared to our previous findings, we hereby further reveal how ACC interacts with PM to sustain self-regulation of one's own emotional state in response to threatening social signals. Moreover, this neural mechanism could account for the description of the "cold-blooded" personality of individuals with alexithymia.
暴露在恐惧信号下会使我们感到受到威胁，并促使我们准备做出适应性反应。在我们之前的研究中，我们提出杏仁核（AMG）和运动前皮层（PM）在观察者对情况所需的运动反应的准备中发挥作用。本实验旨在评估个体差异在情绪反应和调节缺陷相关的人格特质——述情障碍中的作用如何影响与恐惧感知相关的神经网络。我们使用 fMRI 对 34 名健康受试者进行扫描，当他们被动观察恐惧的身体表情时。我们采用维度方法，对所有参与者的恐惧相关大脑区域与述情障碍评分之间进行相关性分析。采用分类方法，我们对（13 名高述情障碍组与 12 名低述情障碍组）进行了组间比较。我们的结果有三个方面。首先，右杏仁核在对恐惧刺激的反应中，其活动与识别情绪的难度水平呈负相关。其次，PM 活动与主观情绪反应性降低有关。第三，组间比较显示，高述情障碍组的前扣带皮层（ACC）活动高于低述情障碍组。此外，在高述情障碍（负相关）和低述情障碍（正相关）个体中，ACC 与 PM 之间的关系呈相反方向。因此，与我们之前的发现相比，我们进一步揭示了 ACC 如何与 PM 相互作用，以维持个体对威胁性社会信号的自身情绪状态的自我调节。此外，这种神经机制可以解释述情障碍个体“冷血”人格的描述。
