A central source of movement variability
A central source of movement variability
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DOI：
10.1016/j.neuron.2006.10.034
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发表时间：
2006-12-21
期刊：
影响因子：
16.2
通讯作者：
Shenoy, Krishna V.
中科院分区：
文献类型：
--
作者：
Churchland, Mark M.;Afshar, Afsheen;Shenoy, Krishna V.
运动是普遍的，有时令人沮丧的，可变的。当这种可变性导致错误时，我们通常会假设在移动过程中出现了错误。同样的假设是由最近的和有影响力的模型的电机控制。这些假设认为，可重复性能的主要限制是神经肌肉噪音，它会在运动发生时破坏运动。另一种假设是，运动变异性出现在运动开始之前，在运动准备期间。我们通过记录单个皮层神经元在高度练习的伸手任务中的准备活动，直接研究了这种可能性。准备性神经活动的微小变化预示着即将到来的接触的微小变化。影响幅度是这样的，至少有一半的观察到的运动变异性可能有其来源在运动准备。因此，即使对于一个高度练习的任务，重复计划相同动作的能力也限制了我们重复执行相同动作的能力。
Movements are universally, sometimes frustratingly, variable. When such variability causes error, we typically assume that something went wrong during the movement. The same assumption is made by recent and influential models of motor control. These posit that the principal limit on repeatable performance is neuromuscular noise that corrupts movement as it occurs. An alternative hypothesis is that movement variability arises before movements begin, during motor preparation. We examined this possibility directly by recording the preparatory activity of single cortical neurons during a highly practiced reach task. Small variations in preparatory neural activity were predictive of small variations in the upcoming reach. Effect magnitudes were such that at least half of the observed movement variability likely had its source during motor preparation. Thus, even for a highly practiced task, the ability to repeatedly plan the same movement limits our ability to repeatedly execute the same movement.