Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning
Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning
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合作而非竞争：双半球 tDCS 和 fMRI 显示同侧半球在运动学习中的作用
DOI：
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发表时间：
2016
影响因子：
5.3
通讯作者：
J. Diedrichsen
中科院分区：
文献类型：
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作者：
S. Waters;T. Wiestler;J. Diedrichsen
同侧运动区和运动前区在运动学习中的作用是什么？一种观点认为，同侧活动抑制对侧运动皮层，因此，抑制同侧区域可以改善运动学习。或者，同侧运动皮层可能在控制和/或学习单侧手部运动中发挥积极作用。我们探讨了这个问题，通过应用双盲双半球经颅直流电刺激（tDCS）在对侧和同侧的运动皮层在一个组间设计在4天的单手显式序列训练的人类参与者。无论阳极是否放置在对侧或同侧运动皮层上，双半球刺激相对于单半球或假刺激产生了实质性的性能增益。这一性能优势似乎得到了两个半球可塑性变化的支持。首先，我们发现，行为优势普遍强烈未经训练的手，这表明tDCS加强效应器独立的代表。第二，在训练后48小时进行的训练序列的速度匹配执行过程中的功能成像显示，相对于假手术组，两个运动皮层的活动持续的，极性无关的增加。这些结果表明，在技能学习过程中，两个运动皮层的合作，而不是竞争性的相互作用，并表明，在unimanual技能学习过程中，双半球脑刺激可能是有益的，因为它利用在同侧半球的可塑性。许多神经康复方法都是基于这样的想法，即有利于提高对侧大脑半球的兴奋性，同时减弱同侧皮层的兴奋性，以减少半球间的抑制。我们观察到，双半球经颅直流电刺激（tDCS）与兴奋性阳极无论是对侧或同侧运动皮层促进运动学习近两倍的强烈unihemispheric tDCS。这些运动学习的增加伴随着两个运动皮层的fMRI激活的增加，这些激活超过了刺激期，以及对未经训练的手的泛化能力的增加。总的来说，我们的研究结果表明，合作，而不是竞争的作用，半球，并意味着它是最有益的利用可塑性在两个半球的神经康复运动缺陷。
What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere. SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex facilitated motor learning nearly twice as strongly as unihemispheric tDCS. These increases in motor learning were accompanied by increases in fMRI activation in both motor cortices that outlasted the stimulation period, as well as increased generalization to the untrained hand. Collectively, our findings suggest a cooperative rather than a competitive role of the hemispheres and imply that it is most beneficial to harness plasticity in both hemispheres in neurorehabilitation of motor deficits.
影响因子：
2.5
作者：
Verstynen, T;Diedrichsen, J;Ivry, RB
通讯作者：
Ivry, RB