Similar scaling of contralateral and ipsilateral cortical responses during graded unimanual force generation
Similar scaling of contralateral and ipsilateral cortical responses during graded unimanual force generation
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DOI：
10.1016/j.neuroimage.2013.02.006
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发表时间：
2014-01-15
期刊：
影响因子：
5.7
通讯作者：
Perrey, S.
中科院分区：
文献类型：
--
作者：
Derosiere, G.;Alexandre, F.;Perrey, S.
半身运动被强烈认为是在大脑皮层的对侧半球的控制下。然而，一些神经影像学研究发现，在单手任务期间，初级感觉运动（SM1）区或喙侧前额叶皮层（PFC）的双侧激活。在一些研究中，这些区域的激活不仅仅是对称的。然而，对称的反应仍然存在很大的争议，特别是对于握力的世代。因此，我们的目的是研究双边SM1和喙PFC区激活在响应分级次最大的力量产生在单侧握力任务。15名健康受试者进行6个级别的力量（范围从5%到50%的MVC）在一个手柄的任务。我们同时测量了激活的双边SM1和喙PFC区通过近红外光谱（NIRS）和肌电图（EMG）活动的双边屈趾浅肌（FDS）肌肉。对于所有研究的力水平，在SM 1区域都发现了对称的激活。在最高级别的力量（即，50%MVC），被动FDS的EMG显著增加，发现同侧头侧PFC激活比相应的对侧头侧PFC激活更强烈。我们建议，视觉引导的控制力水平在一个握任务需要的串扰从同侧到对侧SM1，以科普任务的相对复杂性，类似于复杂的顺序手指运动过程中发生的。我们还提出了另一种解释所观察到的对称性SM1激活，包括（i）同侧皮质脊髓束和（ii）半球间抑制（IHI）机制。被动FDS上EMG活动的增加可能与IHI在50%的MVC下的释放有关。最后，我们的研究结果表明，更大的同侧（右）吻侧PFC激活可能反映了更大的需求，需要注意力控制电机输出在高水平的力量。(C)2013 Elsevier Inc. All rights reserved.
Hemibody movements are strongly considered as being under the control of the contralateral hemisphere of the cerebral cortex. However, some neuroimaging studies have found a bilateral activation of either the primary sensori-motor (SM1) areas or the rostral prefrontal cortex (PFC), during unimanual tasks. More than just bilateral, the activation of these areas was found to be symmetrical in some studies. However, the symmetrical response remains strongly controversial notably for handgrip force generations. We therefore aimed to examine the bilateral SM1 and rostral PFC area activations in response to graded submaximal force generation during a unilateral handgrip task. Fifteen healthy subjects performed 6 levels of force (ranging from 5 to 50% of MVC) during a handgrip task. We concomitantly measured the activation of bilateral SM1 and rostral PFC areas through near-infrared spectroscopy (NIRS) and the electromyographic (EMG) activity of the bilateral flexor digitorum superficialis (FDS) muscles. Symmetrical activation was found over the SM1 areas for all the investigated levels of force. At the highest level of force (i.e., 50% of MVC), the EMG of the passive FDS increased significantly and the ipsilateral rostral PFC activation was found more intense than the corresponding contralateral rostral PFC activation. We suggest that the visuo-guided control of force levels during a handgrip task requires the cross-talk from ipsi- to contralateral SM1 to cope for the relative complexity of the task, similar to that which occurs during complex sequential finger movement. We also propose alternative explanations for the observed symmetrical SM1 activation including (i) the ipsilateral corticospinal tract and (ii) interhemispheric inhibition (IHI) mechanism. The increase in EMG activity over the passive FDS could be associated with a release of IHI at 50% of MVC. Finally, our results suggest that the greater ipsilateral (right) rostral PFC activation may reflect the greater demand of attention required to control the motor output at high levels of force. (C) 2013 Elsevier Inc. All rights reserved.