Pourtois Gilles, Sander David, Andres Michael, Grandjean Didier, Reveret Lionel, Olivier Etienne, Vuilleumier Patrik
Neurology and Imaging of Cognition, Clinic of Neurology and Department of Neurosciences, University Medical Center, 1 rue Michel-Servet, CH-1211 Geneva, Switzerland.
Eur J Neurosci. 2004 Dec;20(12):3507-15. doi: 10.1111/j.1460-9568.2004.03794.x.
Faces are multi-dimensional stimuli bearing important social signals, such as gaze direction and emotion expression. To test whether perception of these two facial attributes recruits distinct cortical areas within the right hemisphere, we used single-pulse transcranial magnetic stimulation (TMS) in healthy volunteers while they performed two different tasks on the same face stimuli. In each task, two successive faces were presented with varying eye-gaze directions and emotional expressions, separated by a short interval of random duration. TMS was applied over either the right somatosensory cortex or the right superior lateral temporal cortex, 100 or 200 ms after presentation of the second face stimulus. Participants performed a speeded matching task on the second face during one of two possible conditions, requiring judgements about either gaze direction or emotion expression (same/different as the first face). Our results reveal a significant task-stimulation site interaction, indicating a selective TMS-related interference following stimulations of somatosensory cortex during the emotional expression task. Conversely, TMS of the superior lateral temporal cortex selectively interfered with the gaze direction task. We also found that the interference effect was specific to the stimulus content in each condition, affecting judgements of gaze shifts (not static eye positions) with TMS over the right superior temporal cortex, and judgements of fearful expressions (not happy expressions) with TMS over the right somatosensory cortex. These results provide for the first time a double dissociation in normal subjects during social face recognition, due to transient disruption of non-overlapping brain regions. The present study supports a critical role of the somatosensory and superior lateral temporal regions in the perception of fear expression and gaze shift in seen faces, respectively.
面部是承载重要社会信号的多维度刺激物，如注视方向和情感表达。为了测试对这两种面部属性的感知是否会在右半球内激活不同的皮质区域，我们在健康志愿者执行针对相同面部刺激的两项不同任务时，使用了单脉冲经颅磁刺激（TMS）。在每项任务中，会呈现两张连续的面部，其注视方向和情感表达各不相同，中间间隔一段随机时长的短暂间隔。在呈现第二个面部刺激后的100或200毫秒，将TMS施加于右侧体感皮层或右侧颞上外侧皮层。在两种可能的条件之一中，参与者在看到第二个面部时执行一项快速匹配任务，要求判断注视方向或情感表达（与第一个面部相同/不同）。我们的结果揭示了显著的任务 - 刺激部位交互作用，表明在情感表达任务中刺激体感皮层后会出现与TMS相关的选择性干扰。相反，颞上外侧皮层的TMS选择性地干扰了注视方向任务。我们还发现，干扰效应在每种条件下都特定于刺激内容，右侧颞上皮层的TMS影响注视转移（而非静态眼睛位置）的判断，右侧体感皮层的TMS影响恐惧表情（而非快乐表情）的判断。这些结果首次在正常受试者的社会面部识别过程中由于非重叠脑区的短暂破坏而提供了双重分离。本研究分别支持了体感区域和颞上外侧区域在感知所看到面部的恐惧表情和注视转移中起关键作用。
