Linking motor imagery to motor execution

描述（由申请人提供）：运动想象是一种积极的认知过程，对人类运动表现具有可测量的影响。运动想象的潜在行为效应在最低限度的体育锻炼后即可表现出来。使用运动想象作为一种潜在的有效的干预措施，以促进早期恢复是有希望的，特别是当患者不能在早期阶段开始身体康复。越来越多的证据表明，想象和实际的运动有着相似的神经基质，包括运动皮层。然而，运动中心/路径之间的关系，在想象和执行运动很少研究。在拟议的研究中，我们计划在正常受试者的运动想象过程中检查运动系统参与的特异性。根据我们以前的研究结果，我们假设，运动中心/途径自愿运动促进阈下水平在运动想象，这些都是专门联系到实际运动的同一个动作在一个强制性的方式。具体目标是：1）采用反应时范式分析运动想象过程中目标肌肉运动通路的运动特异性阈下激活; 2）考察运动想象与运动执行之间的相互作用。在目标1中，我们将比较静息时、不同背景想象运动时和肌肉激活时的运动前时间（PMT），以研究运动想象的运动特异性效应。在反应时间的运动，运动想象的PMT的效果可能会出现的兴奋效应的总和，由于增强皮质脊髓兴奋性，特别是为原动机的想象运动和整体抑制与增加任务的复杂性在运动想象。将使用适当定时的经颅磁刺激（TMS）进一步研究皮质脊髓兴奋性的伴随变化。在目标2中，我们将通过比较对TMS的反应来研究运动想象过程中运动特异性阈下激活与实际运动过程中肌肉激活之间的相互作用。由于相互抑制的中央编程模式，我们预计，TMS的预激活手指屈肌的反应将减少想象中的手指伸展，但可能不会进一步增加想象中的手指屈曲。

DESCRIPTION (provided by applicant): Motor imagery is an active cognitive process that has measurable effects on human motor performance. The latent behavioral effect resulting from motor imagery could be expressed after minimum physical practice. Using motor imagery as a potential efficient intervention to promote early recovery is promising particularly when patients could not start physical rehabilitation in an early stage. Accumulated evidence has demonstrated that imagined and actual movements share similar neural substrates, including the motor cortex. However, the relations between the motor centers/pathways during imagined and executed movements are rarely studied. In the proposed study, we plan to examine specificity of the involvement of the motor system during motor imagery in normal subjects. Based on our previous findings, we hypothesize that motor centers/ pathways for voluntary movements are facilitated at subthreshold levels during motor imagery and that these are specifically linked to actual movement of the same action in an obligatory manner. The specific Aims are: 1) to analyze movement-specific subthreshold activation of motor pathways of the target muscles during motor imagery using a reaction time paradigm; 2) to examine the interactions between motor imagery and motor execution. In Aim 1, we will compare the premotor time (PMT) at rest, during different background imagined movements, and during muscle activation to investigate the movement-specific effect of motor imagery. During reaction time movements, the effect of motor imagery on the PMT could appear as the sum of the excitatory effect due to enhanced corticospinal excitability specifically for the prime mover of the imagined movement and an overall inhibition associated with increased task complexity during motor imagery. The concomitant changes in the corticospinal excitability will be further investigated using appropriately timed transcranial magnetic stimulation (TMS). In Aim 2, we will examine the interactions between movement-specific subthreshold activation during motor imagery and muscle activation during actual movement by comparing the responses to TMS. Due to a centrally programmed pattern of reciprocal inhibition, we expect that the responses to TMS in the preactivated finger flexors will be decreased during imagined finger extension, but may not be further increased during imagined finger flexion.