Bookheimer Susan Y, Wang A Ting, Scott Ashley, Sigman Marian, Dapretto Mirella
Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA.
J Int Neuropsychol Soc. 2008 Nov;14(6):922-32. doi: 10.1017/S135561770808140X.
Functional neuroimaging studies of face processing deficits in autism have typically focused on visual processing regions, such as the fusiform face area (FFA), which have shown reduced activity in autism spectrum disorders (ASD), though inconsistently. We recently reported reduced activity in the inferior frontal region in ASD, implicating impaired mirror-neuron systems during face processing. In the present study, we used fMRI during a face processing task in which subjects had to match faces presented in the upright versus inverted position. Typically developing (TD) children showed a classic behavioral inversion effect, increased reaction time for inverted faces, while this effect was significantly reduced in ASD subjects. The fMRI data showed similar responses in the fusiform face area for ASD and TD children, with both groups demonstrating increased activation for inverted faces. However, the groups did differ in several brain regions implicated in social cognition, particularly prefrontal cortex and amygdala. These data suggest that the behavioral differences in processing upright versus inverted faces for TD children are related not to visual information processing but to the social significance of the stimuli. Our results are consistent with other recent studies implicating frontal and limbic dysfunction during face processing in autism.
针对自闭症患者面部处理缺陷的功能性神经影像学研究通常聚焦于视觉处理区域，比如梭状回面孔区（FFA），该区域在自闭症谱系障碍（ASD）中显示出活动减少，不过并不一致。我们最近报告了ASD患者下额叶区域活动减少，这表明在面部处理过程中镜像神经元系统受损。在本研究中，我们在一项面部处理任务中使用功能磁共振成像（fMRI），让受试者匹配正立和倒置呈现的面孔。正常发育（TD）儿童表现出典型的行为倒置效应，即倒置面孔的反应时间增加，而在ASD受试者中这种效应显著降低。fMRI数据显示，ASD儿童和TD儿童在梭状回面孔区有相似的反应，两组对倒置面孔的激活均增加。然而，两组在涉及社会认知的几个脑区存在差异，特别是前额叶皮质和杏仁核。这些数据表明，TD儿童在处理正立和倒置面孔时的行为差异并非与视觉信息处理有关，而是与刺激的社会意义有关。我们的结果与最近其他一些研究一致，这些研究表明自闭症患者在面部处理过程中存在额叶和边缘系统功能障碍。
