Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
Department of Psychology, MRI Lab Graz, University of Graz, Graz, Austria.
J Neurosci Res. 2022 Mar;100(3):798-826. doi: 10.1002/jnr.25003. Epub 2022 Jan 3.
The human brain functional lateralization has been widely studied over the past decades, and neuroimaging studies have shown how activation of motor areas during hand movement execution (ME) is different according to hand dominance. Nevertheless, there is no research directly investigating the effects of the participant's handedness in a motor imagery (MI) and ME task in both right and left-handed individuals at the cortical and subcortical level. Twenty-six right-handed and 25 left-handed participants were studied using functional magnetic resonance imaging during the imagination and execution of repetitive self-paced movements of squeezing a ball with their dominant, non-dominant, and both hands. Results revealed significant statistical difference (p < 0.05) between groups during both the execution and the imagery task with the dominant, non-dominant, and both hands both at cortical and subcortical level. During ME, left-handers recruited a spread bilateral network, while in right-handers, activity was more lateralized. At the critical level, MI between-group analysis revealed a similar pattern in right and left-handers showing a bilateral activation for the dominant hand. Differentially at the subcortical level, during MI, only right-handers showed the involvement of the posterior cerebellum. No significant activity was found for left-handers. Overall, we showed a partial spatial overlap of neural correlates of MI and ME in motor, premotor, sensory cortices, and cerebellum. Our results highlight differences in the functional organization of motor areas in right and left-handed people, supporting the hypothesis that MI is influenced by the way people habitually perform motor actions.
在过去的几十年里，人类大脑功能的偏侧性已经得到了广泛的研究，神经影像学研究表明，在执行手部运动（ME）时，运动区域的激活根据手的优势而有所不同。然而，目前还没有研究直接调查参与者在右撇子和左撇子个体的运动想象（MI）和 ME 任务中惯用手的影响，无论是在皮质和皮质下水平。我们使用功能磁共振成像研究了 26 名右利手和 25 名左利手参与者，在想象和执行用优势手、非优势手和双手重复自我调节的挤压球运动时。结果表明，在执行和想象任务中，两组之间都存在显著的统计学差异（p<0.05），优势手、非优势手和双手在皮质和皮质下水平都存在差异。在 ME 中，左撇子者招募了一个扩展的双侧网络，而右撇子者的活动则更加偏侧化。在关键水平上，MI 组间分析显示出右利手和左利手之间相似的模式，即对优势手的双侧激活。在皮质下水平上，不同的是，在 MI 期间，只有右撇子者显示出后小脑的参与。左撇子者没有发现显著的活动。总的来说，我们在运动、运动前、感觉皮质和小脑显示了 MI 和 ME 的神经相关性的部分空间重叠。我们的结果强调了右利手和左利手个体运动区域功能组织的差异，支持了 MI 受人们习惯性执行运动动作方式影响的假设。
