Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Republic of Korea.
Clin Neurophysiol. 2012 Nov;123(11):2227-31. doi: 10.1016/j.clinph.2012.04.019. Epub 2012 May 17.
To investigate whether hand muscle repetitive use reduces surround inhibition (SI) as observed in patients with focal hand dystonia, we performed a transcranial magnetic stimulation (TMS) study in 15 healthy right-handed volunteers.
TMS was set to be triggered by self-initiated flexion of the index finger at 3ms after movement onset. Motor evoked potentials (MEPs) of the abductor digiti minimi (ADM) were measured before and at 0, 10, 20 and 30min after 'single' (little finger abduction) and 'dual' (both index finger flexion and little finger abduction) exercise at 0.5Hz for 30min. SI was calculated as (mean control MEP - mean self-triggered MEP)×100/mean control MEP.
Compared to single exercise, dual exercise produced significantly larger and longer-lasting enhancements of self-triggered MEPs, and greater reduction in calculated SIs.
This result demonstrates that synchronized finger exercise can reduce SI between the involved muscles possibly due either to the strengthening of the excitatory connections or to the weakening of the inhibitory connections between them, and may illustrate the association between hand muscle repetitive use and disturbed SI observed in FHD.
The operation of surround inhibition can be reduced by practicing synchronous movements.
为了研究手部肌肉重复性使用是否会导致与局限性手部肌张力障碍患者类似的周围抑制（SI）减弱，我们对 15 名健康右利手志愿者进行了经颅磁刺激（TMS）研究。
TMS 设置为在自我触发的食指弯曲运动开始后 3ms 触发。在“单次”（小指外展）和“双次”（食指弯曲和小指外展）运动后 0、10、20 和 30 分钟，测量小指展肌（ADM）的运动诱发电位（MEP）。SI 计算为（平均对照 MEP-平均自我触发 MEP）×100/平均对照 MEP。
与单次运动相比，双次运动产生了更大且更持久的自我触发 MEP 增强，以及更大的计算 SI 降低。
这一结果表明，同步手指运动可以减少涉及肌肉之间的 SI，这可能是由于兴奋性连接的增强或抑制性连接的减弱所致，并且可能说明了 FHD 中观察到的手部肌肉重复性使用与紊乱的 SI 之间的关联。
通过练习同步运动，可以降低周围抑制的作用。
