Abbruzzese G, Trompetto C, Schieppati M
Department of Neurological Sciences, University of Genoa, Italy.
Exp Brain Res. 1996 Oct;111(3):465-72. doi: 10.1007/BF00228736.
Motor potentials (MEPs) evoked by focal (figure-of-eight coil) transcranial magnetic stimulation of the left motor cortex were recorded from the right opponens pollicis (OP) and flexor digitorum superficialis (FDS) of 14 normal subjects during different motor tasks. Changes in motor cortical excitability under behavioural conditions presumably connected with premotor and supplementary motor area (SMA) activation were investigated by comparing the size of the MEPs obtained during: (1) rest, (2) mental calculus, (3) repetitive left thumb-to-index opposition, (4) mental simulation of the same task with the right hand, (5) sequences of left thumb-to-fingers opposition, and (6) mental simulation of the same sequences with the right hand. MEP size significantly increased in both muscles during sequential movements of the left hand and sequence simulation with the right hand, but not during mental calculus or actual or simulated repetitive movements. The H-reflex evoked in the OP and FDS muscles by electrical stimulation of the median nerve (at wrist and elbow, respectively) under the same experimental conditions did not show significant modifications. The increase in MEP size during non-routine actual or imagined sequences of finger movements supports the view that the SMA is activated under these conditions and that it exerts a direct facilitatory influence on the motor cortex.
在14名正常受试者进行不同运动任务期间，通过对左侧运动皮层进行局灶性（8字形线圈）经颅磁刺激，从右侧拇对掌肌（OP）和指浅屈肌（FDS）记录运动诱发电位（MEP）。通过比较在以下情况下获得的MEP大小，研究了行为条件下可能与运动前区和辅助运动区（SMA）激活相关的运动皮层兴奋性变化：（1）休息；（2）心算；（3）左手拇指与示指反复对掌；（4）用右手对相同任务进行心理模拟；（5）左手拇指与其他手指反复对掌序列；（6）用右手对相同序列进行心理模拟。在左手连续运动和右手模拟序列期间，两块肌肉的MEP大小均显著增加，但在心算或实际或模拟的重复运动期间则没有。在相同实验条件下，通过分别在腕部和肘部对正中神经进行电刺激，在OP和FDS肌肉中诱发的H反射未显示出显著变化。在非习惯性的实际或想象的手指运动序列期间MEP大小的增加支持了以下观点：在这些条件下SMA被激活，并且它对运动皮层施加直接的易化影响。
