Restricted repetitive behavior (RRB) is one of two behavioral domains required for the diagnosis of autism spectrum disorder (ASD). Neuroimaging is widely used to study brain alterations associated with ASD and the domain of social and communication deficits, but there has been less work regarding brain alterations linked to RRB. We utilized neuroimaging data from the National Institute of Mental Health Data Archive to assess basal ganglia and cerebellum structure in a cohort of children and adolescents with ASD compared to typically developing (TD) controls. We evaluated regional gray matter volumes from T1-weighted anatomical scans and assessed diffusion-weighted scans to quantify white matter microstructure with free-water imaging. We also investigated the interaction of biological sex and ASD diagnosis on these measures, and their correlation with clinical scales of RRB. Individuals with ASD had significantly lower free-water corrected fractional anisotropy (FAT) and higher free-water (FW) in cortico-basal ganglia white matter tracts. These microstructural differences did not interact with biological sex. Moreover, both FAT and FW in basal ganglia white matter tracts significantly correlated with measures of RRB. In contrast, we found no significant difference in basal ganglia or cerebellar gray matter volumes. The basal ganglia and cerebellar regions in this study were selected due to their hypothesized relevance to RRB. Differences between ASD and TD individuals that may occur outside the basal ganglia and cerebellum, and their potential relationship to RRB, were not evaluated. These new findings demonstrate that cortico-basal ganglia white matter microstructure is altered in ASD and linked to RRB. FW in cortico-basal ganglia and intra-basal ganglia white matter was more sensitive to group differences in ASD, whereas cortico-basal ganglia FAT was more closely linked to RRB. In contrast, basal ganglia and cerebellar volumes did not differ in ASD. There was no interaction between ASD diagnosis and sex-related differences in brain structure. Future diffusion imaging investigations in ASD may benefit from free-water estimation and correction in order to better understand how white matter is affected in ASD, and how such measures are linked to RRB.

中文翻译：

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皮质基底节白质微观结构与自闭症谱系障碍的受限重复行为有关

限制性重复行为 (RRB) 是诊断自闭症谱系障碍 (ASD) 所需的两个行为领域之一。神经影像学广泛用于研究与 ASD 相关的大脑改变以及社交和沟通缺陷领域，但与 RRB 相关的大脑改变的研究较少。我们利用美国国家心理健康研究所数据档案馆的神经影像数据来评估一组患有自闭症谱系障碍 (ASD) 的儿童和青少年与正常发育 (TD) 对照组的基底神经节和小脑结构。我们评估了 T1 加权解剖扫描的区域灰质体积，并评估了扩散加权扫描，以通过自由水成像量化白质微观结构。我们还研究了生物性别和 ASD 诊断在这些指标上的相互作用，以及它们与 RRB 临床量表的相关性。患有 ASD 的个体在皮质基底节白质束中具有显着较低的自由水校正分数各向异性（FAT）和较高的自由水（FW）。这些微观结构差异与生物性别无关。此外，基底节白质束中的 FAT 和 FW 均与 RRB 测量值显着相关。相比之下，我们发现基底神经节或小脑灰质体积没有显着差异。本研究中选择基底神经节和小脑区域是因为假设它们与 RRB 相关。尚未评估 ASD 和 TD 个体之间可能发生在基底节和小脑之外的差异，以及它们与 RRB 的潜在关系。这些新发现表明，自闭症谱系障碍 (ASD) 中皮质基底节白质微结构发生改变，并与 RRB 相关。皮质基底节和基底节内白质中的 FW 对 ASD 的群体差异更敏感，而皮质基底节 FAT 与 RRB 的相关性更密切。相比之下，自闭症谱系障碍 (ASD) 患者的基底神经节和小脑体积没有差异。自闭症谱系障碍（ASD）诊断与大脑结构的性别相关差异之间没有相互作用。未来 ASD 的扩散成像研究可能会受益于自由水估计和校正，以便更好地了解 ASD 中白质如何受到影响，以及这些措施如何与 RRB 联系起来。