BMC Neurosci:右脑额下回镜像神经元障碍或导致自闭症

阿斯伯格综合征又名亚斯伯格症候群，是自闭症的一种，其重要特征是交际困难、兴趣狭隘及重复特定行为。但和其他类型的自闭症相比，患者的语言及认知能力仍可发育。

佐藤弥等人让患有阿斯伯格综合征等的12名患者和13名正常人观看动画上活动的表情，然后利用功能磁共振成像检测他们脑部活动的变化。结果发现，在发育障碍的患者中，其右脑额叶下部的额下回活动降低的比例非常高，这里的镜像神经元被认为具有能够将自己的行动与他人的行动联系在一起分析的功能。

研究小组认为，镜像神经元没有顺利发挥作用的可能性很高，同时还确认，与分析表情信息有关的大脑部位与额下回的结合也出现减弱，这也应该是导致交际困难的原因之一。相关论文已经刊登在英国医学杂志《BMC神经科学》网络版上。

doi:10.1186/1471-2202-13-99

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Impaired social brain network for processing dynamic facial expressions in autism spectrum disorders

Wataru Sato, Motomi Toichi, Shota Uono and Takanori Kochiyama

Background Impairment of social interaction via facial expressions represents a core clinical feature of autism spectrum disorders (ASD). However, the neural correlates of this dysfunction remain unidentified. Because this dysfunction is manifested in real-life situations, we hypothesized that the observation of dynamic, compared with static, facial expressions would reveal abnormal brain functioning in individuals with ASD. We presented dynamic and static facial expressions of fear and happiness to individuals with high-functioning ASD and to age- and sex-matched typically developing controls and recorded their brain activities using functional magnetic resonance imaging (fMRI). Result Regional analysis revealed reduced activation of several brain regions in the ASD group compared with controls in response to dynamic versus static facial expressions, including the middle temporal gyrus (MTG), fusiform gyrus, amygdala, medial prefrontal cortex, and inferior frontal gyrus (IFG). Dynamic causal modeling analyses revealed that bi-directional effective connectivity involving the primary visual cortex-MTG-IFG circuit was enhanced in response to dynamic as compared with static facial expressions in the control group. Group comparisons revealed that all these modulatory effects were weaker in the ASD group than in the control group.

Conclusions These results suggest that weak activity and connectivity of the social brain network underlie the impairment in social interaction involving dynamic facial expressions in individuals with ASD.