Ioannides Andreas A, Poghosyan Vahe, Dammers Jürgen, Streit Marcus
Laboratory for Human Brain Dynamics, BSI, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.
Neuroimage. 2004 Oct;23(2):473-82. doi: 10.1016/j.neuroimage.2004.06.023.
Processing of facial information is distributed across several brain regions, as has been shown recently in many neuroimaging studies. Disturbances in accurate face processing have been repeatedly demonstrated in different stages of schizophrenia. Recently, electroencephalography (EEG) and tomographic analysis of average magnetoencephalographic (MEG) data were used to define the latencies of significant regional brain activations in healthy and schizophrenic subjects elicited during the recognition of facial expression of emotions. The current study re-examines these results using tomographic analysis of single trial MEG data. In addition to the areas identified by the analysis of the average MEG data, statistically significant activity is identified in several other areas, including a sustained increase in the right amygdala activity in response to emotional faces in schizophrenic subjects. The single trial analysis demonstrated that the reduced activations identified from the average MEG signal of schizophrenic subjects is due to high variability across single trials rather than reduced activity in each single trial. In control subjects, direct measures of linkage demonstrate distinct stages of processing of emotional faces within well-defined network of brain regions. Activity in each node of the network, confined to 30 to 40 ms latency windows, is linked to earlier and later activations of the other nodes of the network. In schizophrenic subjects, no such well-defined stages of processing were observed. Instead, the activations, although strong were poorly linked to each other, managing only isolated links between pairs of areas.
面部信息的处理分布在多个脑区，正如最近许多神经影像学研究所示。在精神分裂症的不同阶段，准确的面部处理障碍已被反复证实。最近，脑电图（EEG）和平均脑磁图（MEG）数据的断层分析被用于确定健康受试者和精神分裂症患者在识别面部表情时引起的重要区域脑激活的潜伏期。本研究使用单次试验MEG数据的断层分析重新审视了这些结果。除了通过平均MEG数据分析确定的区域外，在其他几个区域也发现了具有统计学意义的活动，包括精神分裂症患者对情绪面孔的反应中右侧杏仁核活动持续增加。单次试验分析表明，从精神分裂症患者的平均MEG信号中识别出的激活减少是由于单次试验之间的高变异性，而不是每次单次试验中的活动减少。在对照受试者中，直接的关联测量表明在明确的脑区网络中情绪面孔处理有不同阶段。网络中每个节点的活动，限制在30到40毫秒的潜伏期窗口内，与网络中其他节点的早期和晚期激活相关联。在精神分裂症患者中，没有观察到如此明确的处理阶段。相反，激活虽然强烈，但彼此之间的关联很差，仅在区域对之间存在孤立的联系。
