Individuals with autism spectrum disorder (ASD) frequently present with impairments in motor skills (e.g., limb coordination, handwriting and balance), which are observed across the lifespan but remain largely untreated. Many adults with ASD may thus experience adverse motor outcomes in aging, when physical decline naturally occurs. The 'hand knob' of the sensorimotor cortex is an area that is critical for motor control of the fingers and hands. However, this region has received little attention in ASD research, especially in adults after midlife. The hand knob area of the precentral (PrC_hand) and postcentral (PoC_hand) gyri was semi-manually delineated in 49 right-handed adults (25 ASD, 24 typical comparison [TC] participants, aged 41-70 years). Using multimodal (T1-weighted, diffusion-weighted, and resting-state functional) MRI, we examined the morphology, ipsilateral connectivity and laterality of these regions. Correlations between hand knob measures with motor skills and autism symptoms, and between structural and functional connectivity measures were also investigated. The right PrC_hand volume was greater, and typical leftward laterality of PrC_hand and PoC_hand volume was lower in the ASD than the TC group. Furthermore, we observed increased mean diffusivity of the right PoC-PrC_hand u-fibers in the ASD group. In the ASD group, right PoC-PrC_hand u-fiber volume was negatively associated with current autism severity, and positively associated with right PoC-PrC_hand functional connectivity (FC). Correlations of hand knob measures were observed with manual dexterity and coordination skills but did not survive multiple comparisons correction. Our findings suggest decreased morphological laterality and u-fiber connectivity of the sensorimotor network involved in hand function in middle-aged adults with ASD. The altered morphology may relate to atypical functional asymmetries found in ASD earlier in life, but additionally, could reflect an overreliance on right hemisphere motor circuits over time. The right PoC-PrC_hand u-fibers may underlie compensatory self-regulation of unwanted core motor behaviors seen in ASD.

中文翻译：

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减少中年自闭症患者的手把手区域不对称性和感觉运动 u 纤维连接性降低

患有自闭症谱系障碍 (ASD) 的个体经常表现出运动技能（例如，肢体协调、书写和平衡）的障碍，这些障碍在整个生命周期中都会被观察到，但在很大程度上仍未得到治疗。因此，当自然发生身体衰退时，许多患有 ASD 的成年人可能会在衰老过程中出现不良的运动结果。感觉运动皮层的“把手”是一个对手指和手的运动控制至关重要的区域。然而，这个区域在 ASD 研究中很少受到关注，尤其是在中年以后的成年人中。中央前（PrC_手）和中央后（PoC_手）的把手区域) gyri 在 49 名右利手成人（25 名 ASD，24 名典型比较 [TC] 参与者，年龄 41-70 岁）中半手动描绘。使用多模态（T1 加权、弥散加权和静息状态功能）MRI，我们检查了这些区域的形态、同侧连通性和侧向性。还研究了手柄测量与运动技能和自闭症症状之间的相关性，以及结构和功能连接性测量之间的相关性。与 TC 组相比，ASD 中右侧 PrC_手体积更大，典型的 PrC_手向左偏侧和 PoC_手体积更低。此外，我们观察到ASD 组中右侧 PoC-PrC_手u 纤维的平均扩散率增加。在 ASD 组中，右侧 PoC-PrC_手u 纤维量与当前的自闭症严重程度呈负相关，与右侧 PoC-PrC_手功能连接 (FC)呈正相关。用手的灵巧性和协调能力观察到了手旋钮测量的相关性，但在多重比较校正后没有幸免于难。我们的研究结果表明，在患有 ASD 的中年人中，参与手部功能的感觉运动网络的形态侧向性和 u 纤维连接性降低。改变的形态可能与早年 ASD 中发现的非典型功能不对称有关，但另外，随着时间的推移，可能反映出对右半球运动回路的过度依赖。正确的 PoC-PrC_手u 纤维可能是 ASD 中看到的不需要的核心运动行为的补偿性自我调节的基础。