Lohse Keith R, Sherwood David E
Department of Psychology and Neuroscience, University of Colorado, Boulder, 345 UCB, Boulder, CO 80309, USA.
Acta Psychol (Amst). 2012 Jul;140(3):236-45. doi: 10.1016/j.actpsy.2012.05.009. Epub 2012 Jun 7.
Although the effects of attention on movement execution are well documented behaviorally, much less research has been done on the neurophysiological changes that underlie attentional focus effects. This study presents two experiments exploring effects of attention during an isometric plantar-flexion task using surface electromyography (sEMG). Participants' attention was directed either externally (towards the force plate they were pushing against) or internally (towards their own leg, specifically the agonist muscle). Experiment 1 tested the effects of attention on accuracy and efficiency of force produced at three target forces (30, 60, and 100% of the maximum voluntary contraction; MVC). An internal focus of attention reduced the accuracy of force being produced and increased cocontraction of the antagonist muscle. Error on a given trial was positively correlated with the magnitude of cocontraction on that trial. Experiment 2 tested the effects of attention on muscular fatigue at 30, 60 and 100%MVC. An internal focus of attention led to less efficient intermuscular coordination, especially early in the contraction. These results suggest that an internal focus of attention disrupts efficient motor control in force production resulting in increased cocontraction, which potentially explains other neuromechanical findings (e.g. reduced functional variability with an internal focus).
尽管注意力对动作执行的影响在行为学上已有充分记录，但对于注意力集中效应背后的神经生理学变化的研究却少得多。本研究提出了两个实验，利用表面肌电图（sEMG）探索等长跖屈任务中注意力的影响。参与者的注意力被引导至外部（朝向他们所推的力板）或内部（朝向他们自己的腿部，特别是主动肌）。实验1测试了在三种目标力（最大自主收缩的30%、60%和100%；MVC）下注意力对产生的力的准确性和效率的影响。内部注意力集中降低了所产生力的准确性，并增加了拮抗肌的共同收缩。给定试验中的误差与该试验中共同收缩的幅度呈正相关。实验2测试了在30%、60%和100%MVC下注意力对肌肉疲劳的影响。内部注意力集中导致肌肉间协调效率降低，尤其是在收缩早期。这些结果表明，内部注意力集中会干扰力产生过程中的有效运动控制，导致共同收缩增加，这可能解释了其他神经力学发现（例如，内部注意力集中时功能变异性降低）。
