Department of Neuropsychiatry, University of Tokyo, Japan.
Biol Psychiatry. 2010 Dec 15;68(12):1141-7. doi: 10.1016/j.biopsych.2010.07.012.
Recent literature suggests that the inferior frontal gyrus, especially its posterior portion, has an important role in imitation and social reciprocity and in the pathophysiology of their disturbance in autism spectrum disorders (ASD). However, the structural abnormality of this region has not fully been clarified in subjects with ASD.
Here we obtained magnetic resonance images from 13 right-handed men with high-functioning ASD (Asperger disorder [n = 10] or autism [n = 3]) and from 11 age-, parental socioeconomic background-, and intelligence quotient-matched right-handed typical men. A reliable manual tracing methodology was employed to measure the gray matter volume of the pars opercularis, corresponding to Brodmann area 44, and the pars triangularis, corresponding to Brodmann area 45.
A significant gray matter volume reduction of both the pars opercularis and triangularis was found bilaterally in the subjects with ASD compared with the typical control subjects. The effect size seemed to be larger for pars opercularis (1.25) than for pars triangularis (.90). The reduced volume of right as well as total pars opercularis showed a significant association with the increased severity of social communication problems in the ASD group.
The current findings support an important role of pars opercularis, a center of the mirror neuron system, in the pathophysiology of ASD.
近期文献表明，额下回，尤其是其后部，在模仿和社会互惠中具有重要作用，并且在自闭症谱系障碍（ASD）中其功能障碍的病理生理学中也具有重要作用。然而，ASD 患者该区域的结构异常尚未完全阐明。
我们从 13 名右利手的高功能 ASD 患者（其中包括 10 名阿斯伯格障碍患者和 3 名自闭症患者）和 11 名年龄、父母社会经济背景和智商匹配的右利手正常男性中获得了磁共振图像。采用可靠的手动追踪方法测量了额下回的脑灰质体积，对应于布罗德曼 44 区，以及额三角区的脑灰质体积，对应于布罗德曼 45 区。
与正常对照组相比，ASD 患者双侧额下回和额三角的脑灰质体积均显著减少。额下回的脑灰质体积减少的效应量似乎大于额三角（分别为 1.25 和.90）。右额下回和总额下回的体积减少与 ASD 组社会交往问题严重程度的增加显著相关。
目前的研究结果支持额下回，即镜像神经元系统的中心，在 ASD 的病理生理学中具有重要作用。
