The neural correlates of learned motor acuity.
The neural correlates of learned motor acuity.
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DOI：
10.1152/jn.00897.2013
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发表时间：
2014-08
影响因子：
2.5
通讯作者：
L. Shmuelof;Juemin Yang;B. Caffo;P. Mazzoni;J. Krakauer
中科院分区：
文献类型：
--
作者：
L. Shmuelof;Juemin Yang;B. Caffo;P. Mazzoni;J. Krakauer
我们最近将运动技能学习的一个组成部分定义为“运动敏锐度”，量化为任务的速度-准确性权衡函数的转变。这些变化主要是由于运动变异性的减少。为了确定运动敏锐度改善的神经相关性，我们设计了一个与磁共振脑成像兼容的运动任务，要求受试者在视觉指导下进行精细控制的手腕运动。受试者在第1天和第5天进行成像，同时进行这项任务，并在第2、3和4天在扫描仪外接受培训。通过将移动时间限制为固定持续时间，避免了第1天和第5天之间性能变化的潜在混淆。训练后，受试者表现出显着增加的成功率和减少试验的试验变异性的训练任务，但不是一个未经训练的控制任务，没有变化的平均轨迹。训练任务的变异性降低与对侧初级运动和运动前皮质区以及同侧小脑的激活增加有关。一项全球非局部化多变量分析证实，学习与整体大脑激活的增加有关。我们认为，运动敏锐度是通过增加在对侧运动皮质区和同侧小脑，这可能反映了增加的信噪比在运动输出和改善状态估计反馈校正，分别招募的神经元的数量。
We recently defined a component of motor skill learning as "motor acuity," quantified as a shift in the speed-accuracy trade-off function for a task. These shifts are primarily driven by reductions in movement variability. To determine the neural correlates of improvement in motor acuity, we devised a motor task compatible with magnetic resonance brain imaging that required subjects to make finely controlled wrist movements under visual guidance. Subjects were imaged on day 1 and day 5 while they performed this task and were trained outside the scanner on intervening days 2, 3, and 4. The potential confound of performance changes between days 1 and 5 was avoided by constraining movement time to a fixed duration. After training, subjects showed a marked increase in success rate and a reduction in trial-by-trial variability for the trained task but not for an untrained control task, without changes in mean trajectory. The decrease in variability for the trained task was associated with increased activation in contralateral primary motor and premotor cortical areas and in ipsilateral cerebellum. A global nonlocalizing multivariate analysis confirmed that learning was associated with increased overall brain activation. We suggest that motor acuity is acquired through increases in the number of neurons recruited in contralateral motor cortical areas and in ipsilateral cerebellum, which could reflect increased signal-to-noise ratio in motor output and improved state estimation for feedback corrections, respectively.