Nordahl Christine Wu, Iosif Ana-Maria, Young Gregory S, Perry Lee Michael, Dougherty Robert, Lee Aaron, Li Deana, Buonocore Michael H, Simon Tony, Rogers Sally, Wandell Brian, Amaral David G
The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California at Davis, Sacramento, CA 95817 USA.
The MIND Institute, University of California at Davis, School of Medicine, 2805 50th Street, Sacramento, CA 95817 USA ; Department of Public Health Sciences, School of Medicine, University of California at Davis, Davis, CA 95616 USA.
Mol Autism. 2015 May 13;6:26. doi: 10.1186/s13229-015-0005-4. eCollection 2015.
Abnormalities in the corpus callosum have been reported in individuals with autism spectrum disorder (ASD), but few studies have evaluated young children. Sex differences in callosal organization and diffusion characteristics have also not been evaluated fully in ASD.
Structural and diffusion-weighted images were acquired in 139 preschool-aged children with ASD (112 males/27 females) and 82 typically developing (TD) controls (53 males/29 females). Longitudinal scanning at two additional annual time points was carried out in a subset of these participants. Callosal organization was evaluated using two approaches: 1) diffusion tensor imaging (DTI) tractography to define subregions based on cortical projection zones and 2) as a comparison to previous studies, midsagittal area analysis using Witelson subdivisions. Diffusion measures of callosal fibers were also evaluated.
Analyses of cortical projection zone subregions revealed sex differences in the patterns of altered callosal organization. Relative to their sex-specific TD counterparts, both males and females with ASD had smaller regions dedicated to fibers projecting to superior frontal cortex, but patterns differed in callosal subregions projecting to other parts of frontal cortex. While males with ASD had a smaller callosal region dedicated to the orbitofrontal cortex, females with ASD had a smaller callosal region dedicated to the anterior frontal cortex. There were also sex differences in diffusion properties of callosal fibers. While no alterations were observed in males with ASD relative to TD males, mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were all increased in females with ASD relative to TD females. Analyses of Witelson subdivisions revealed a decrease in midsagittal area of the corpus callosum in both males and females with ASD but no regional differences in specific subdivisions. Longitudinal analyses revealed no diagnostic or sex differences in the growth rate or change in diffusion measures of the corpus callosum from 3 to 5 years of age.
There are sex differences in the pattern of altered corpus callosum neuroanatomy in preschool-aged children with ASD.
已有报道称自闭症谱系障碍（ASD）患者存在胼胝体异常，但很少有研究评估幼儿。ASD中胼胝体组织和扩散特征的性别差异也尚未得到充分评估。
对139名学龄前ASD儿童（112名男性/27名女性）和82名发育正常（TD）的对照儿童（53名男性/29名女性）进行了结构和扩散加权成像。在这些参与者的一个子集中，于另外两个年度时间点进行了纵向扫描。胼胝体组织通过两种方法进行评估：1）扩散张量成像（DTI）纤维束成像，基于皮质投射区定义子区域；2）作为与先前研究的比较，使用维特森分区进行矢状中面面积分析。还评估了胼胝体纤维的扩散测量值。
对皮质投射区子区域的分析揭示了胼胝体组织改变模式中的性别差异。相对于其性别特异性的TD对应者，患有ASD的男性和女性投射到额上皮质的纤维区域都较小，但投射到额叶其他部位的胼胝体子区域模式不同。患有ASD的男性胼胝体中投射到眶额皮质的区域较小，而患有ASD的女性胼胝体中投射到额前皮质的区域较小。胼胝体纤维的扩散特性也存在性别差异。相对于TD男性，患有ASD的男性未观察到改变，但相对于TD女性，患有ASD的女性平均扩散率（MD）、轴向扩散率（AD）和径向扩散率（RD）均增加。对维特森分区的分析显示，患有ASD的男性和女性胼胝体矢状中面面积均减小，但特定分区无区域差异。纵向分析显示，3至5岁时胼胝体的生长速率或扩散测量值变化在诊断或性别方面无差异。
学龄前ASD儿童胼胝体神经解剖结构改变模式存在性别差异。
