van der Gaag Christiaan, Minderaa Ruud B, Keysers Christian
University of Groningen, Groningen, The Netherlands.
Soc Neurosci. 2007;2(3-4):179-222. doi: 10.1080/17470910701376878.
Facial expressions contain both motor and emotional components. The inferior frontal gyrus (IFG) and posterior parietal cortex have been considered to compose a mirror neuron system (MNS) for the motor components of facial expressions, while the amygdala and insula may represent an "additional" MNS for emotional states. Together, these systems may contribute to our understanding of facial expressions. Here we further examine this possibility. In three separate event-related fMRI experiment, subjects had to (1) observe (2) discriminate and (3) imitate facial expressions. Stimuli were dynamic neutral, happy, fearful and disgusted facial expressions, and in Experiments 1 and 2, an additional pattern motion condition. Importantly, during each experiment, subjects were unaware of the nature of the next experiments. Results demonstrate that even passive viewing of facial expressions activates a wide network of brain regions that were also involved in the execution of similar expressions, including the IFG/insula and the posterior parietal cortex. Only a subset of these regions responded more during the observation of facial than pattern motion (bilateral ventral IFG, bilateral STS/MTG, bilateral amygdala, SMA). While the viewing of facial expressions recruited similar brain regions in all three experiments, adding an active task (discrimination, imitation) augmented the magnitude of these activations. Brain activations reflected differences in observed facial expressions, with emotional expressions activating relatively more the insula/frontal operculum, and neutral ones (blowing up the cheeks) the somatosensory cortices (SII). Using movies, fear activated the amygdala and disgust the insula, but other emotions activated these structures to a similar degree.
面部表情包含运动和情感成分。额下回（IFG）和顶叶后皮质被认为构成了一个用于面部表情运动成分的镜像神经元系统（MNS），而杏仁核和脑岛可能代表了一个用于情绪状态的“额外”MNS。这些系统共同作用，可能有助于我们对面部表情的理解。在此，我们进一步探讨这种可能性。在三个独立的事件相关功能磁共振成像实验中，受试者必须（1）观察（2）辨别和（3）模仿面部表情。刺激物为动态的中性、快乐、恐惧和厌恶的面部表情，在实验1和2中，还有一个额外的图案运动条件。重要的是，在每个实验过程中受试者都不知道下一个实验的性质。结果表明，即使是被动观看面部表情也会激活广泛的脑区网络，这些脑区也参与了类似表情的执行，包括额下回/脑岛和顶叶后皮质。在观察面部表情时，这些区域中只有一部分比观察图案运动时反应更强烈（双侧腹侧额下回、双侧颞上沟/颞中回、双侧杏仁核、辅助运动区）。虽然在所有三个实验中观看面部表情都激活了类似的脑区，但增加一个主动任务（辨别、模仿）会增强这些激活的程度。脑激活反映了观察到的面部表情的差异，情绪表情相对更多地激活脑岛/额盖，而中性表情（鼓起脸颊）则激活体感皮质（第二体感区）。使用电影时，恐惧激活杏仁核，厌恶激活脑岛，但其他情绪对这些结构的激活程度相似。
