a The Brain in Action Laboratory, Department of Kinesiology and Physical Education , University of Lethbridge , Lethbridge , AB , Canada.
Laterality. 2015 May;20(3):287-305. doi: 10.1080/1357650X.2014.961472. Epub 2014 Sep 26.
We have recently shown that actions with similar kinematic requirements, but different end-state goals may be supported by distinct neural networks. Specifically, we demonstrated that when right-handed individuals reach-to-grasp food items with intent to eat, they produce smaller maximum grip apertures (MGAs) than when they grasp the same item with intent to place it in a location near the mouth. This effect was restricted to right-handed movements; left-handed movements showed no difference between tasks. The current study investigates whether (and to which side) the effect may be lateralized in left-handed individuals. Twenty-one self-identified left-handed participants grasped food items of three different sizes while grasp kinematics were captured via an Optotrak Certus motion capture array. A main effect of task was identified wherein the grasp-to-eat action generated significantly smaller MGAs than did the grasp-to-place action. Further analysis revealed that similar to the findings in right-handed individuals, this effect was significant only during right-handed movements. Upon further inspection however, we found individual differences in the magnitude and direction of the observed lateralization. These results underscore the evolutionary significance of the grasp-to-eat movement in producing population-level right-handedness in humans as well as highlighting the heterogeneity of the left-handed population.
我们最近的研究表明，具有相似运动学要求但不同目标的动作可能由不同的神经网络支持。具体来说，我们证明了当右利手个体意图进食时伸手去抓食物时，他们产生的最大握力开口（MGA）比意图将食物放在靠近嘴的位置时要小。这种效应仅限于右手运动；左手运动在任务之间没有差异。本研究调查了左利手个体是否（以及向哪一侧）存在这种效应的偏侧化。21 名自我认定的左利手参与者在三种不同大小的食物物品上进行抓握，同时通过 Optotrak Certus 运动捕捉阵列捕获抓握运动学。任务的主要效应表明，抓握进食的动作产生的 MGA 明显小于抓握放置的动作。进一步的分析表明，与右利手个体的发现相似，这种效应仅在右手运动时显著。然而，进一步检查发现，观察到的偏侧化的幅度和方向存在个体差异。这些结果强调了在人类中产生群体水平的右利手时，抓握进食动作的进化意义，同时突出了左利手人群的异质性。
