Repetitive and restricted behaviors and interests (RRBI) are core symptoms of autism with a complex entity and are commonly categorized into ‘motor-driven’ and ‘cognitively driven’. RRBI symptomatology depends on the individual’s clinical environment limiting the understanding of RRBI physiology, particularly their associated neuroanatomical structures. The complex RRBI heterogeneity needs to explore the whole RRBI spectrum by integrating the clinical context [autistic individuals, their relatives and typical developing (TD) individuals]. We hypothesized that different RRBI dimensions would emerge by exploring the whole spectrum of RRBI and that these dimensions are associated with neuroanatomical signatures—involving cortical and subcortical areas. A sample of 792 individuals composed of 267 autistic subjects, their 370 first-degree relatives and 155 TD individuals was enrolled in the study. We assessed the whole patterns of RRBI in each individual by using the Repetitive Behavior Scale-Revised and the Yale-Brown Obsessive Compulsive Scale. We estimated brain volumes using MRI scanner for a subsample of the subjects (n = 152, 42 ASD, 89 relatives and 13 TD). We first investigated the dimensionality of RRBI by performing a principal component analysis on all items of these scales and included all the sampling population. We then explored the relationship between RRBI-derived factors with brain volumes using linear regression models. We identified 3 main factors (with 30.3% of the RRBI cumulative variance): Factor 1 (FA1, 12.7%) reflected mainly the ‘motor-driven’ RRBI symptoms; Factor 2 and 3 (respectively, 8.8% and 7.9%) gathered mainly Y-BOCS related items and represented the ‘cognitively driven’ RRBI symptoms. These three factors were significantly associated with the right/left putamen volumes but with opposite effects: FA1 was negatively associated with an increased volume of the right/left putamen conversely to FA2 and FA3 (all uncorrected p < 0.05). FA1 was negatively associated with the left amygdala (uncorrected p < 0.05), and FA2 was positively associated with the left parietal structure (uncorrected p = 0.001). Our results suggested 3 coherent RRBI dimensions involving the putamen commonly and other structures according to the RRBI dimension. The exploration of the putamen’s integrative role in RSBI needs to be strengthened in further studies.

中文翻译：

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探索自闭症重复和受限行为和兴趣 (RRBI) 的多维性质：神经解剖学相关性和临床意义

重复和受限的行为和兴趣（RRBI）是自闭症的核心症状，具有复杂的实体，通常分为“运动驱动”和“认知驱动”。RRBI 症状取决于个体的临床环境，限制了对 RRBI 生理学的理解，特别是其相关的神经解剖结构。复杂的 RRBI 异质性需要通过整合临床背景 [自闭症个体、其亲属和典型发育中 (TD) 个体] 来探索整个 RRBI 谱系。我们假设通过探索 RRBI 的整个范围，会出现不同的 RRBI 维度，并且这些维度与涉及皮质和皮质下区域的神经解剖学特征相关。该研究纳入了 792 名个体样本，其中包括 267 名自闭症受试者、他们的 370 名一级亲属和 155 名 TD 个体。我们使用修订版重复行为量表和耶鲁-布朗强迫量表评估了每个人的 RRBI 整体模式。我们使用 MRI 扫描仪估算了受试者子样本的脑容量（n = 152、42 名 ASD、89 名亲属和 13 名 TD）。我们首先通过对这些量表的所有项目进行主成分分析来研究 RRBI 的维数，并包括所有抽样总体。然后，我们使用线性回归模型探讨了 RRBI 衍生因素与脑容量之间的关系。我们确定了 3 个主要因素（占 RRBI 累积方差的 30.3%）： 因素 1（FA1，12.7%）主要反映“运动驱动”的 RRBI 症状；因子 2 和 3（分别为 8.8% 和 7.9%）主要收集 Y-BOCS 相关项目，代表“认知驱动”的 RRBI 症状。这三个因素与右/左壳核体积显着相关，但具有相反的影响：FA1 与右/左壳核体积增加呈负相关，而 FA2 和 FA3 则相反（均未校正 p < 0.05）。FA1 与左侧杏仁核呈负相关（未校正 p < 0.05），FA2 与左侧顶叶结构呈正相关（未校正 p = 0.001）。我们的结果提出了 3 个连贯的 RRBI 维度，通常涉及壳核和根据 RRBI 维度的其他结构。壳核在 RSBI 中的整合作用的探索需要进一步研究。