Tokimura H, Ridding M C, Tokimura Y, Amassian V E, Rothwell J C
MRC Human Movement and Balance Unit, Institute of Neurology, Queen Square, London, UK.
Electroencephalogr Clin Neurophysiol. 1996 Aug;101(4):263-72. doi: 10.1016/0924-980x(96)95664-7.
Pairs of threshold magnetic stimuli were applied over the motor cortex at interstimulus intervals of 1-6 ms, and EMG responses recorded from the relaxed or active first dorsal interosseous muscle of 7 normal subjects. In relaxed subjects, when the interval between the stimuli was around 1.0-1.5 ms, 2.5-3.0 ms or 4.5 ms or later, the size of the response to the pair of stimuli was much greater than the algebraic sum of the response to each stimulus alone. During contraction, fewer peaks of facilitation were observed. Facilitation was evident if the stimuli were 0.9-1.1 times threshold in the relaxed state, and 1.0-1.1 times threshold during voluntary contraction. Experiments using either magnetic followed by anodal electric stimulation, or pairs of anodal electric stimuli, suggested that the facilitation most likely occurred within the cerebral motor cortex. Given the timings at which facilitation is prominent, it seems likely that it reflects interactions between circuits normally responsible for production of I-waves.
在7名正常受试者的放松或主动收缩的第一背侧骨间肌上，以1 - 6毫秒的刺激间隔对运动皮层施加成对的阈下磁刺激，并记录肌电图反应。在放松的受试者中，当刺激间隔约为1.0 - 1.5毫秒、2.5 - 3.0毫秒或4.5毫秒及更晚时，对成对刺激的反应大小远大于单独对每个刺激的反应的代数和。在收缩过程中，观察到的易化峰值较少。如果刺激在放松状态下为阈强度的0.9 - 1.1倍，在自主收缩时为阈强度的1.0 - 1.1倍，则易化明显。使用磁刺激后接阳极电刺激或成对阳极电刺激的实验表明，易化最可能发生在大脑运动皮层内。鉴于易化突出时的时间，似乎它反映了通常负责产生I波的神经回路之间的相互作用。
