Target Uncertainty During Motor Decision-Making: The Time Course of Movement Variability Reveals the Effect of Different Sources of Uncertainty on the Control of Reaching Movements
Target Uncertainty During Motor Decision-Making: The Time Course of Movement Variability Reveals the Effect of Different Sources of Uncertainty on the Control of Reaching Movements
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DOI：
10.3389/fpsyg.2019.00041
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发表时间：
2019-01-28
影响因子：
3.8
通讯作者：
Hermsdoerfer, Joachim
中科院分区：
文献类型：
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作者：
Krueger, Melanie;Hermsdoerfer, Joachim
运动决策的基本过程最近引起了相当多的科学关注，重点是将来自感觉运动控制研究的经验证据与决策的心理学理论和计算模型相结合。关于运动决策的实证研究表明，目标导向到达动作的运动学对运动规划中的目标不确定性水平非常敏感。然而，作为影响汽车决策过程的相关因素的不确定性来源还没有得到充分的考虑。在本研究中，我们检验了目标不确定性来源对运动决策有影响的假设，这一假设可以通过分析运动执行过程中的运动变异性来验证。10名健康的年轻人进行了三个区块，每个区块有66次目标定向到达运动试验，通过这些试验，操控了运动开始时到达目标不确定性的来源和水平(“无不确定性”、“外在不确定性”和“内在不确定性”)。使用光学运动跟踪系统记录右手食指的指尖位置。分析了标准运动学测量(即路径长度和运动持续时间)以及指尖位置在动作执行过程中和动作结束时的变异性。与之前的研究一致，我们发现高水平的外在目标不确定性会导致整体运动持续时间增加，这可能归因于在这种情况下，与内在和无目标不确定性相比，路径长度增加(所有P<；0.001)。运动持续时间和路径长度在后两种情况下没有表现出任何差异。然而，运动变异性的时间进程分析显示，这两种情况之间存在显著差异，在存在内在目标不确定性的情况下(条件x采样点：P=0.01)，指尖位置的变异性增加，尽管显著低于在高外部目标不确定性存在时(P
The processes underlying motor decision-making have recently caught considerable amount of scientific attention, focusing on the integration of empirical evidence from sensorimotor control research with psychological theories and computational models on decision-making. Empirical studies on motor decision-making suggest that the kinematics of goal-directed reaching movements are sensitive to the level of target uncertainty during movement planning. However, the source of uncertainty as a relevant factor influencing the process of motor decision-making has not been sufficiently considered, yet. In this study, we test the assumption that the source of target uncertainty has an effect on motor decision-making, which can be proven by analyzing movement variability during the time course of movement execution. Ten healthy young adults performed three blocks with 66 trials of goal-directed reaching movements in each block, across which the source and level of reach target uncertainty at movement onset were manipulated ("no uncertainty", "extrinsic uncertainty", and "intrinsic uncertainty"). Fingertip position of the right index finger was recorded using an optical motion tracking system. Standard kinematic measures (i.e., path length and movement duration) as well as variability of fingertip position across the time course of movement execution and at movement end were analyzed. In line with previous studies, we found that a high level of extrinsic target uncertainty leads to increased overall movement duration, which could be attributed to increased path length in this condition, as compared to intrinsic and no target uncertainty (all p < 0.001). Movement duration and path length did not show any differences between the latter two conditions. However, the time course analysis of movement variability revealed significant differences between these two conditions, with increased variability of fingertip position in the presence of intrinsic target uncertainty (Condition x Sampling point: p = 0.01), though considerably less than under high extrinsic target uncertainty (p