Dissociating timing and coordination as functions of the cerebellum.
Dissociating timing and coordination as functions of the cerebellum.
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DOI：
10.1523/jneurosci.0061-07.2007
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发表时间：
2007-06-06
期刊：
影响因子：
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通讯作者：
Shadmehr R
中科院分区：
文献类型：
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作者：
Diedrichsen J;Criscimagna-Hemminger SE;Shadmehr R
小脑在运动控制中的功能是一个长期存在的谜题，因为小脑损伤与时间和协调缺陷有关。计时是指在运动之间根据内部时间表示产生一致间隔的能力。相反，协调是一个状态依赖的控制过程，其中对一个效应器的运动命令依赖于另一个效应器的预测状态。在这里，我们考虑了一个由两个组成部分组成的任务，一个手臂运动和一个大拇指等距按压。我们发现，当这两个部分暂时重叠时，大脑通过对手臂状态的估计来控制拇指。相比之下，当这些成分在时间上没有重叠时，大脑完全根据内部对时间的估计来控制拇指。使用功能磁共振成像，我们对比了这两种情况，发现在状态依赖控制中，与手臂运动同侧的小脑V小叶始终更加活跃。当大脑学习时间依赖控制时，与状态依赖控制相比，小脑的任何区域都没有表现出持续的活动增加。相反，与时间依赖的控制相关的持续活动是在左脑半球沿Sylvian裂的语言区域发现的。我们认为，时间和协调是运动控制的行为不同模式，小脑前部是状态依赖运动控制的关键节点，计算一个效应器（如手臂）的预测状态估计，以协调另一个效应器（拇指）的动作。
The function of the cerebellum in motor control is a long-standing puzzle because cerebellar damage is associated with both timing and coordination deficits. Timing is the ability to produce consistent intervals between movements based on an internal representation of time. Coordination, in contrast, is a state-dependent control process where motor commands to one effector depend on the predicted state of another effector. Here we considered a task consisting of two components, an arm movement and an isometric press with the thumb. We found that when the two components temporally overlapped, the brain controlled the thumb using an estimate of the state of the arm. In contrast, when the components did not temporally overlap, the brain controlled the thumb solely based on an internal estimate of time. Using fMRI, we contrasted these two conditions and found that lobule V of the cerebellum ipsilateral to the arm movement was consistently more activated during state-dependent control. When the brain learned time-dependent control, no region of the cerebellum showed consistently increased activity compared to state-dependent control. Rather, the consistent activity associated with time-dependent control was found in language areas of the left cerebral hemisphere along the Sylvian fissure. We suggest that timing and coordination are behaviorally distinct modes of motor control, and that the anterior cerebellum is a crucial node in state-dependent motor control, computing a predictive state estimate of one effector (e.g. the arm) in order to coordinate actions of another effector (the thumb).