Department of General Psychology, University of Padova, Padova, Italy.
The School of Medicine, University of St. Andrews, St. Andrews, UK.
Neuroscientist. 2021 Feb;27(1):88-103. doi: 10.1177/1073858420937657. Epub 2020 Jul 29.
The development and persistence of laterality is a key feature of human motor behavior, with the asymmetry of hand use being the most prominent. The idea that asymmetrical functions of the hands reflect asymmetries in terms of structural and functional brain organization has been tested many times. However, despite advances in laterality research and increased understanding of this population-level bias, the neural basis of handedness remains elusive. Recent developments in diffusion magnetic resonance imaging enabled the exploration of lateralized motor behavior also in terms of white matter and connectional neuroanatomy. Despite incomplete and partly inconsistent evidence, structural connectivity of both intrahemispheric and interhemispheric white matter seems to differ between left and right-handers. Handedness was related to asymmetry of intrahemispheric pathways important for visuomotor and visuospatial processing (superior longitudinal fasciculus), but not to projection tracts supporting motor execution (corticospinal tract). Moreover, the interindividual variability of the main commissural pathway corpus callosum seems to be associated with handedness. The review highlights the importance of exploring new avenues for the study of handedness and presents the latest state of knowledge that can be used to guide future neuroscientific and genetic research.
左右偏侧性的发展和持续是人类运动行为的一个关键特征，其中手的使用不对称性最为突出。用手的不对称功能来反映结构和功能大脑组织的不对称的观点已经被多次检验。然而，尽管在偏侧性研究方面取得了进展，并增加了对这种人群偏向的理解，但手性的神经基础仍然难以捉摸。扩散磁共振成像的最新发展使得人们能够从白质和连接神经解剖学的角度来探索偏侧化的运动行为。尽管证据不完整且部分不一致，但左右利手者之间的半球内和半球间白质的结构连接似乎存在差异。手性与对视觉运动和视觉空间处理很重要的半球内通路的不对称性有关（胼胝体上纵束），但与支持运动执行的投射束无关（皮质脊髓束）。此外，主要连合径路胼胝体的个体间变异性似乎与手性有关。这篇综述强调了探索研究手性的新途径的重要性，并介绍了可用于指导未来神经科学和遗传学研究的最新知识状态。
