Wang Haha, Zhou Hong, Guo Yihao, Gao Lei, Xu Haibo
Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China.
Siemens MR Collaboration, Siemens Healthcare, Guangzhou, China.
Front Hum Neurosci. 2021 Aug 13;15:687965. doi: 10.3389/fnhum.2021.687965. eCollection 2021.
The brain structural and functional basis of lateralization in handedness is largely unclear. This study aimed to explore this issue by using voxel-mirrored homotopic connectivity (VMHC) measured by resting-state functional MRI (R-fMRI) and gray matter asymmetry index (AI) by high-resolution anatomical images. A total of 50 healthy subjects were included, among them were 13 left-handers, 24 right-handers, and 13 mixed-handers. Structural and R-fMRI data of all subjects were collected. There were significant differences in VMHC among the three groups in lateral temporal-occipital, orbitofrontal, and primary hand motor regions. Meanwhile, there were significant differences in AI that existed in medial prefrontal, superior frontal, and superior temporal regions. Besides, the correlation analysis showed that the closer the handedness score to the extreme of the left-handedness (LH), the stronger the interhemispheric functional connectivity, as well as more leftward gray matter. In general, left/mixed-handedness (MH) showed stronger functional homotopy in the transmodal association regions that depend on the integrity of the corpus callosum, but more variable in primary sensorimotor cortices. Furthermore, the group differences in VMHC largely align with that in AI. We located the specific regions for LH/MH from the perspective of structural specification and functional integration, suggesting the plasticity of hand movement and different patterns of emotional processing.
利手偏侧化的脑结构和功能基础在很大程度上尚不清楚。本研究旨在通过使用静息态功能磁共振成像（R-fMRI）测量的体素镜像同伦连接性（VMHC）和高分辨率解剖图像的灰质不对称指数（AI）来探讨这个问题。总共纳入了50名健康受试者，其中包括13名左利手者、24名右利手者和13名混合利手者。收集了所有受试者的结构和R-fMRI数据。三组在颞枕外侧、眶额和主要手部运动区域的VMHC存在显著差异。同时，在内侧前额叶、额上回和颞上回区域的AI也存在显著差异。此外，相关性分析表明，利手得分越接近左利手（LH）极端情况，半球间功能连接越强，灰质也越向左偏移。总体而言，左利手/混合利手（MH）在依赖胼胝体完整性的跨模态联合区域表现出更强的功能同伦性，但在主要感觉运动皮层中变化更大。此外，VMHC的组间差异在很大程度上与AI的差异一致。我们从结构特异性和功能整合的角度确定了LH/MH的特定区域，这表明手部运动的可塑性和不同的情绪处理模式。
