Data from: Increasing cognitive load attenuates right arm swing in healthy human walking

Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task—primarily involving left hemisphere structures—would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18–80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry—an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right—increased significantly under dual-task conditions in those aged 40–59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.

人类的手臂摆动无论从视觉观感还是主观感受上都呈现高度自动化的特征，但越来越多的研究表明，包括大脑皮层在内的高级中枢参与了运动控制的诸多环节。在行走过程中附加认知任务会加剧手臂摆动的不对称性，但该不对称性的特征与内在机制仍未明确。我们提出如下假说：该效应具有偏侧化特征，以激活左侧半球结构为主的Stroop色词命名任务（Stroop word-colour naming task）仅会抑制右侧手臂摆动。我们对83名年龄介于18至80岁的健康受试者开展了步态记录：受试者分别在跑步机上自然行走，以及执行一致型、冲突型Stroop任务时完成数据采集。手臂摆动不对称性的核心量化指标——基于三维手腕运动轨迹构建的指数（正值代表右侧手臂摆动幅度相对更小）——在双任务条件下，40至59岁受试者的该指数显著升高，而60岁以上受试者的升高幅度更为显著，这一现象由右侧手臂屈曲幅度降低所驱动。在执行运动-认知双任务的人群中，右侧手臂摆动减弱似乎是普遍现象，这证实了大脑在运动行为中发挥着关键作用。60岁以下女性对该效应的抵抗性出人意料，这揭示了运动控制层级链条之上存在此前未被发现的性别差异。