Vaalto Selja, Julkunen Petro, Säisänen Laura, Könönen Mervi, Määttä Sara, Karhu Jari
Department of Clinical Neurophysiology, Helsinki University Central Hospital, Helsinki, Finland.
Neuroreport. 2013 Aug 7;24(11):596-600. doi: 10.1097/WNR.0b013e3283628636.
Our aim was to study long-term plasticity in the organization of cortical muscle representations due to extensive motor training for different skills. We were especially interested in whether skill-specific demands on independent hand muscle movements and synchronous leg muscle movements are reflected differently in the reorganization of muscle representations. We used navigated transcranial magnetic stimulation to estimate the size of cortical representations of opponens pollicis, abductor digiti minimi, and tibialis anterior muscles in five string instrument players, five figure skaters, and five controls. The extent of the representation area was presented as an amplitude-area curve showing the spatial distribution of motor evoked potentials. The size of representation areas was compared between the dominant and nondominant hemispheres and between the groups. The representation area of the left abductor digiti minimi (critical for reaching right tones) in the right, nondominant hemisphere was smaller in string players and the representation area of the tibialis anterior in the dominant hemisphere (critical for jumps) was larger in figure skaters when compared with controls. Reorganization in the motor cortex may differ depending upon the skill and an individual muscle's role in the skill. A smaller representation area of the independently used hand muscle in masters of fine motor skills may reflect long-term plasticity toward more focused representation, which may be beneficial in accurate and discrete cortical control of the muscle. Larger cortical representations are related to skill demanding coactivation of proximal and distal lower limb muscles.
我们的目的是研究因不同技能的广泛运动训练而导致的皮质肌肉表征组织的长期可塑性。我们特别感兴趣的是，对手部独立肌肉运动和腿部同步肌肉运动的特定技能要求，在肌肉表征的重组中是否有不同的体现。我们使用导航经颅磁刺激来估计五名弦乐器演奏者、五名花样滑冰运动员和五名对照组人员的拇对掌肌、小指展肌和胫骨前肌的皮质表征大小。表征区域的范围以振幅-面积曲线呈现，显示运动诱发电位的空间分布。比较优势半球和非优势半球之间以及各组之间的表征区域大小。与对照组相比，弦乐器演奏者右侧非优势半球中左手小指展肌（对弹奏正确音调至关重要）的表征区域较小，花样滑冰运动员优势半球中胫骨前肌（对跳跃至关重要）的表征区域较大。运动皮层的重组可能因技能以及单个肌肉在技能中的作用而异。精细运动技能大师中独立使用的手部肌肉的表征区域较小，可能反映了向更集中表征的长期可塑性，这可能有利于对肌肉进行精确和离散的皮质控制。较大的皮质表征与要求近端和远端下肢肌肉共同激活的技能有关。
