Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen 6525 EN, The Netherlands
Department of Psychology, Rutgers University, Camden, NJ 08102.
eNeuro. 2020 Apr 27;7(2). doi: 10.1523/ENEURO.0492-19.2020. Print 2020 Mar/Apr.
Behavioral studies have shown that the human motor system recycles motor parameters of previous actions, such as movement amplitude, when programming new actions. Shifting motor plans toward a new action forms a particularly severe problem for patients with Parkinson's disease (PD), a disorder that, in its early stage, is dominated by basal ganglia dysfunction. Here, we test whether this action selection deficit in Parkinson's patients arises from an impaired ability to recycle motor parameters shared across subsequent actions. Parkinson's patients off dopaminergic medication ( = 16) and matched healthy controls ( = 16) performed a task that involved moving a handheld dowel over an obstacle in the context of a sequence of aiming movements. Consistent with previous research, healthy participants continued making unnecessarily large hand movements after clearing the obstacle (defined as "hand path priming effect"), even after switching movements between hands. In contrast, Parkinson's patients showed a reduced hand path priming effect, i.e., they performed biomechanically more efficient movements than controls, but only when switching movements between hands. This effect correlated with disease severity, such that patients with more severe motor symptoms had a smaller hand path priming effect. We propose that the basal ganglia mediate recycling of movement parameters across subsequent actions.
行为研究表明，人类运动系统在规划新动作时会重复先前动作的运动参数，例如运动幅度。对于帕金森病（PD）患者来说，将运动计划转移到新动作尤其成问题，因为这种疾病在早期主要由基底神经节功能障碍引起。在这里，我们测试帕金森病患者的这种动作选择缺陷是否源于他们在后续动作中共享的运动参数的回收能力受损。帕金森病患者在不服用多巴胺能药物时（ = 16）和匹配的健康对照组（ = 16）在手执圆棒穿越障碍物的环境中执行一系列瞄准动作任务。与之前的研究一致，健康参与者在清除障碍物后（定义为“手路径启动效应”）继续进行不必要的大手移动，即使在手之间切换动作也是如此。相比之下，帕金森病患者的手路径启动效应降低，即他们的运动比对照组更具生物力学效率，但仅在手之间切换动作时才如此。这种效应与疾病严重程度相关，即运动症状更严重的患者手路径启动效应更小。我们提出，基底神经节介导后续动作之间运动参数的重复使用。
