Silvert Laetitia, Lepsien Jöran, Fragopanagos Nickolaos, Goolsby Brian, Kiss Monika, Taylor John G, Raymond Jane E, Shapiro Kimron L, Eimer Martin, Nobre Anna C
University of Oxford, UK.
Neuroimage. 2007 Nov 1;38(2):357-66. doi: 10.1016/j.neuroimage.2007.07.023. Epub 2007 Aug 7.
Recent studies have cast doubts on the appealing idea that the processing of threat-related stimuli in the amygdala is unconstrained by the availability of attentional resources. However, these studies exclusively used face stimuli presented at fixation and it is unclear whether their conclusion can apply to peripheral face stimuli. Thus, we designed an experiment in which we manipulated the perceptual attentional load of the task used to divert attention from peripheral face stimuli: participants were presented simultaneously with four peripheral pictures (two faces, either both neutral or both fearful, and two houses) that were slightly tilted, and had to match two of these pictures (defined by their position on the screen) either for orientation of the tilt or for identity. The identity task was confirmed to involve greater attentional load than the orientation task by differences in accuracy, reaction times, subsequent face recognition performance, and patterns of activation in several cortical regions. In the orientation task, ignored fearful faces led to stronger activation in the right amygdala than ignored neutral faces. However, this differential response was abolished when participants performed the difficult identity-matching task. Thus, emotional processing of peripheral faces in the amygdala also appears to depend on the available perceptual attentional resources.
最近的研究对这样一个颇具吸引力的观点提出了质疑，即杏仁核中与威胁相关刺激的处理不受注意力资源可用性的限制。然而，这些研究仅使用了固定位置呈现的面部刺激，尚不清楚它们的结论是否适用于外周面部刺激。因此，我们设计了一项实验，在该实验中，我们操纵了用于转移对外周面部刺激注意力的任务的感知注意力负荷：向参与者同时呈现四张略微倾斜的外周图片（两张面部图片，要么都是中性表情，要么都是恐惧表情，以及两张房屋图片），参与者必须根据倾斜方向或身份匹配其中两张图片（由它们在屏幕上的位置定义）。通过准确性、反应时间、后续面部识别表现以及几个皮质区域的激活模式差异，证实身份匹配任务比方向匹配任务涉及更大的注意力负荷。在方向匹配任务中，被忽视的恐惧面部比被忽视的中性面部在右侧杏仁核中引发更强的激活。然而，当参与者执行困难的身份匹配任务时，这种差异反应就消失了。因此，杏仁核对外周面部的情绪处理似乎也依赖于可用的感知注意力资源。
