Pryweller Jennifer R, Schauder Kimberly B, Anderson Adam W, Heacock Jessica L, Foss-Feig Jennifer H, Newsom Cassandra R, Loring Whitney A, Cascio Carissa J
Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
Department of Clinical and Social Sciences in Psychology, University of Rochester, Rochester, NY, USA.
Neuroimage Clin. 2014 Oct 13;6:379-87. doi: 10.1016/j.nicl.2014.09.018. eCollection 2014.
Autism spectrum disorder (ASD) has been characterized by atypical socio-communicative behavior, sensorimotor impairment and abnormal neurodevelopmental trajectories. DTI has been used to determine the presence and nature of abnormality in white matter integrity that may contribute to the behavioral phenomena that characterize ASD. Although atypical patterns of sensory responding in ASD are well documented in the behavioral literature, much less is known about the neural networks associated with aberrant sensory processing. To address the roles of basic sensory, sensory association and early attentional processes in sensory responsiveness in ASD, our investigation focused on five white matter fiber tracts known to be involved in these various stages of sensory processing: superior corona radiata, centrum semiovale, inferior longitudinal fasciculus, posterior limb of the internal capsule, and splenium. We acquired high angular resolution diffusion images from 32 children with ASD and 26 typically developing children between the ages of 5 and 8. We also administered sensory assessments to examine brain-behavior relationships between white matter integrity and sensory variables. Our findings suggest a modulatory role of the inferior longitudinal fasciculus and splenium in atypical sensorimotor and early attention processes in ASD. Increased tactile defensiveness was found to be related to reduced fractional anisotropy in the inferior longitudinal fasciculus, which may reflect an aberrant connection between limbic structures in the temporal lobe and the inferior parietal cortex. Our findings also corroborate the modulatory role of the splenium in attentional orienting, but suggest the possibility of a more diffuse or separable network for social orienting in ASD. Future investigation should consider the use of whole brain analyses for a more robust assessment of white matter microstructure.
自闭症谱系障碍（ASD）的特征表现为非典型的社会交流行为、感觉运动障碍以及异常的神经发育轨迹。弥散张量成像（DTI）已被用于确定白质完整性异常的存在及性质，这些异常可能导致ASD所特有的行为现象。尽管行为学文献中已充分记录了ASD中感觉反应的非典型模式，但对于与异常感觉处理相关的神经网络却知之甚少。为了探究基本感觉、感觉关联和早期注意过程在ASD感觉反应中的作用，我们的研究聚焦于已知参与这些不同感觉处理阶段的五条白质纤维束：放射冠上部、半卵圆中心、下纵束、内囊后肢和压部。我们采集了32名5至8岁ASD儿童和26名发育正常儿童的高角分辨率扩散图像。我们还进行了感觉评估，以检验白质完整性与感觉变量之间的脑-行为关系。我们的研究结果表明，下纵束和压部在ASD非典型感觉运动和早期注意过程中起调节作用。发现触觉防御性增强与下纵束中各向异性分数降低有关，这可能反映了颞叶边缘结构与顶下小叶之间的异常连接。我们的研究结果还证实了压部在注意定向中的调节作用，但表明ASD中可能存在一个更弥散或可分离的社交定向网络。未来的研究应考虑使用全脑分析来更全面地评估白质微观结构。
