Center for General Education, Nagasaki Institute of Applied Science, Nagasaki, Japan.
Physiol Meas. 2011 Dec;32(12):1929-39. doi: 10.1088/0967-3334/32/12/004. Epub 2011 Nov 2.
The brain function controlling muscle force production is not yet fully understood. The purpose of this study was to examine bilateral primary motor cortex (M1) oxygenation during static-handgrip exercises performed with the right hand (60% maximal voluntary contraction; 10 s exercise/75 s rest; five sets). Twelve healthy, right-handed male subjects participated in this study. Near-infrared spectroscopy probes were positioned over the bilateral M1 to measure cortical oxygenation during handgrip exercises. The maximum values of the changes in concentrations of oxyhemoglobin (HbO(2)) and deoxyhemoglobin (Hb) across the trials (i) did not change significantly during the contralateral M1 activation (p > 0.05), whereas (ii) in the case of the ipsilateral M1 activation a significant (p < 0.05) decrease in HbO(2) and a significant (p < 0.01) decrease in Hb could be measured. The activation in ipsilateral M1 at the fifth trial was significantly decreased compared with that in the first trial (HbO(2): p < 0.001; Hb: p < 0.001). The present results suggest that the ipsilateral M1 is recruited during the motor task in compensation for the contralateral M1 and the habituation to motor task might alter the efficiency for interaction of the ipsilateral M1 to the contralateral M1. The interhemispheric interaction might change due to habituation to motor task.
大脑控制肌肉力量产生的功能尚未被完全理解。本研究的目的是在右手进行静态握力练习（60%最大自主收缩；10 秒运动/75 秒休息；五组）时检查双侧初级运动皮层（M1）的氧合作用。12 名健康的右利手男性参与了这项研究。近红外光谱探头放置在双侧 M1 上方，以测量握力练习期间的皮质氧合作用。在整个试验过程中，（i）对侧 M1 激活时，氧合血红蛋白（HbO2）和脱氧血红蛋白（Hb）浓度变化的最大值没有明显变化（p>0.05），而（ii）在同侧 M1 激活时，HbO2 明显减少（p<0.05），Hb 明显减少（p<0.01）。与第一次试验相比，第五次试验时同侧 M1 的激活明显降低（HbO2：p<0.001；Hb：p<0.001）。本研究结果表明，在运动任务中，同侧 M1 被募集以补偿对侧 M1，并且运动任务的习惯化可能改变同侧 M1 与对侧 M1 相互作用的效率。由于对运动任务的习惯化，半球间的相互作用可能会发生变化。
