Laboratoire de Sciences Cognitives et Psycholinguistique, CNRS/EHESS/DEC-ENS, Paris 75005, France.
Neuropsychologia. 2012 Dec;50(14):3736-44. doi: 10.1016/j.neuropsychologia.2012.10.025. Epub 2012 Nov 6.
Facial expressions are known to impact observers' behavior, even when they are not consciously identifiable. Relying on visual crowding, a perceptual phenomenon whereby peripheral faces become undiscriminable, we show that participants exposed to happy vs. neutral crowded faces rated the pleasantness of subsequent neutral targets accordingly to the facial expression's valence. Using functional magnetic resonance imaging (fMRI) along with psychophysiological interaction analysis, we investigated the neural determinants of this nonconscious preference bias, either induced by static (i.e., pictures) or dynamic (i.e., videos) facial expressions. We found that while static expressions activated primarily the ventral visual pathway (including task-related functional connectivity between the fusiform face area and the amygdala), dynamic expressions triggered the dorsal visual pathway (i.e., posterior partietal cortex) and the substantia innominata, a structure that is contiguous with the dorsal amygdala. As temporal cues are known to improve the processing of visible facial expressions, the absence of ventral activation we observed with crowded videos questions the capacity to integrate facial features and facial motions without awareness. Nevertheless, both static and dynamic facial expressions activated the hippocampus and the orbitofrontal cortex, suggesting that nonconscious preference judgments may arise from the evaluation of emotional context and the computation of aesthetic evaluation.
面部表情被认为会影响观察者的行为,即使它们无法被有意识地识别。我们利用视觉拥挤现象,即周边的面孔变得难以区分的感知现象,表明参与者接触到快乐与中性的拥挤面孔后,会根据表情的效价相应地评估后续中性目标的愉悦度。我们使用功能磁共振成像 (fMRI) 结合心理生理交互分析,研究了这种非意识偏好偏见的神经决定因素,无论是由静态(即图片)还是动态(即视频)面部表情引起的。我们发现,虽然静态表情主要激活了腹侧视觉通路(包括梭状回面部区域和杏仁核之间的任务相关功能连接),但动态表情触发了背侧视觉通路(即顶叶后区)和无名质,无名质与背侧杏仁核相邻。由于时间线索已知可以改善可见面部表情的处理,我们观察到拥挤视频中缺乏腹侧激活,这质疑了在无意识的情况下整合面部特征和面部运动的能力。然而,静态和动态面部表情都激活了海马体和眶额皮层,这表明非意识偏好判断可能源于对情绪背景的评估和对审美评估的计算。