Optimal compensation for changes in task-relevant movement variability
Optimal compensation for changes in task-relevant movement variability
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DOI：
10.1523/jneurosci.1906-05.2005
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发表时间：
2005-08-03
影响因子：
5.3
通讯作者：
Banks, MS
中科院分区：
文献类型：
--
作者：
Trommershäuser, J;Gepshtein, S;Banks, MS
有效的调度规划应考虑到在执行计划调度时可能出现的错误的后果。这些错误可能是由于感官的不确定性或运动规划和生产的可变性。我们研究了人类的能力，以弥补变化的感觉估计和运动生产的条件下，可变性是人为增加的实验者。受试者迅速指向一个有相邻惩罚区域的目标区域。目标和惩罚命中产生金钱奖励和损失。我们操纵的任务相关的变化，通过扰动视觉反馈的手指位置在运动过程中。在每次试验中，反馈以随机幅度向随机方向移动，导致任务相关可变性增加。受试者无法对抗这种形式的干扰。奖励和惩罚是基于扰动，视觉指定的手指位置。受试者在< 120次试验中迅速获得了对他们新的变异性的估计，并相应地调整了他们的目标点。我们将受试者的表现与最佳运动规划者的表现进行了比较，以最大化预期收益。他们的表现是一致的，从一个最佳的运动规划，完美地补偿外部施加的变化，任务相关的变异性的预期。当暴露于新的刺激配置时，目标点在第一次试验中发生了变化，而没有显示出任何可检测到的趋势。这些结果表明，受试者能够改变他们的指向策略存在外部施加的噪声。此外，他们设法更新他们的任务相关的可变性估计，并将此估计转移到新的刺激配置。
Effective movement planning should take into account the consequences of possible errors in executing a planned movement. These errors can result from either sensory uncertainty or variability in movement planning and production. We examined the ability of humans to compensate for variability in sensory estimation and movement production under conditions in which variability is increased artificially by the experimenter. Subjects rapidly pointed at a target region that had an adjacent penalty region. Target and penalty hits yielded monetary rewards and losses. We manipulated the task-relevant variability by perturbing visual feedback of finger position during the movement. The feedback was shifted in a random direction with a random amplitude in each trial, causing an increase in the task-relevant variability. Subjects were unable to counteract this form of perturbation. Rewards and penalties were based on the perturbed, visually specified finger position. Subjects rapidly acquired an estimate of their new variability in < 120 trials and adjusted their aim points accordingly. We compared subjects' performance to the performance of an optimal movement planner maximizing expected gain. Their performance was consistent with that expected from an optimal movement planner that perfectly compensated for externally imposed changes in task-relevant variability. When exposed to novel stimulus configurations, aim points shifted in the first trial without showing any detectable trend across trials. These results indicate that subjects are capable of changing their pointing strategy in the presence of externally imposed noise. Furthermore, they manage to update their estimate of task-relevant variability and to transfer this estimate to novel stimulus configurations.