运动技能水平与躯体感觉输入对运动表象的影响

The effects of motor skill level and somatosensory input on motor imagery: An fMRI study on basketball free shot

运动表象质量与运动技能水平有关,运动表象质量随着运动技能水平的提高而上升。器械使用可使人脑产生可塑性改变,使用者会将器械纳入身体图式。然而,两者影响运动表象的神经心理机制还不清楚。本研究采用功能性磁共振成像探析篮球运动员与新手在不同持球条件下表象投篮时脑功能活动的差异。结果表明运动员表象质量较好,镜像神经系统激活高于新手;持球条件下运动员表象质量显著高于不持球条件下,镜像神经系统激活程度显著低于不持球条件下。研究说明持器械可以显著提高运动员的表象质量,器械使用带来镜像神经系统的可塑性变化。

The behavioral performance and neural responses of imagining a motor task may be different in individuals with different motor skill levels. Utilization of special instrument induces plastic changes in the brain in the way that tool users combine the tool in their body schema. However, the neural correlates underlying these effects are still not clear. Using functional magnetic resonance imaging （fMRI）, we investigated the effects of motor skill level and somatosensory input on motor imagery. We tested 12 basketball players and 12 novices when they performed kinesthetic motor imagery of basketball free shot under with-ball and without-ball conditions. Motor imagery duration was calculated. Motor imagery strategy and quality were measured with self-evaluation questionnaires. Field training was implemented and the physical performance of the task was recorded before the main experiment. The time difference between the duration for motor imagery and physical performance was smaller in basketball players than that in novices. The motor imagery strategy scores with self-evaluation questionnaire were same in two groups, indicating that all participants performed kinesthetic imagery successfully. The general kinesthetic and visual imagery abilities between groups showed no significant differences whereas basketball players showed better kinesthetic imagery quality for free shot movements. The scores for the quality of both kinesthetic and visual imagery were higher under with-ball than that under without-ball condition in both groups, suggesting that participants in both groups performed better motor imagery under with-ball condition. fMRI analysis revealed （1） basketball players showed greater mirror neuron system activation relative to novices; （2） the activation of mirror neuron system in basketball players were lower in with-ball compared to without-ball condition. Moreover, the activity of right inferior frontal gyrus was negatively correlated with the self-evaluated kinesthetic imagery scores only for the basketball players. We conclude that better motor imagery is related to higher level motor skill. The application of task- specific instrument may be required for this facilitation effect. Utilization of special instrument induces plastic changes in mirror neuron system. The findings may provide evidence for the implication of motor imagery with utilization of specific instrument in the promotion of motor skill.