Mima T, Nagamine T, Ikeda A, Yazawa S, Kimura J, Shibasaki H
Department of Brain Pathophysiology, Kyoto University School of Medicine, Japan.
Ann Neurol. 1998 May;43(5):598-607. doi: 10.1002/ana.410430507.
Myoclonus-associated cortical activities were studied by simultaneous recording of a magnetoencephalogram and an electroencephalogram in 6 patients with cortical myoclonus due to various causes. Cortical activities were averaged, with respect to the precise onset of the myoclonic jerk, to evaluate the myoclonus-associated cortical magnetic fields. The estimated generator of their earliest peak was localized at the contralateral precentral gyrus in all patients. As judged from the direction of the electrical current, surface positive activity preceding the electromyographic discharge was detected in 3 patients with cortical reflex myoclonus and in 1 patient with possible corticobasal degeneration. In contrast, in the remaining 2 patients (Lennox-Gastaut syndrome and Alzheimer's disease), magnetic fields time-locked to the myoclonic jerk were associated with surface negative activity at the precentral cortex. The present study, applying for the first time an off-line jerk-locked back-averaging analysis to magnetoencephalography, demonstrated the important role of the precentral cortex in generating spontaneous myoclonus. It is most likely that the differing polarity of the electromagnetic activity reflects the differing activation patterns within the cortical laminar structure in the precentral area, underlying the generation of various types of myoclonus.
通过同步记录6例因各种原因导致皮质肌阵挛患者的脑磁图和脑电图，对肌阵挛相关的皮质活动进行了研究。针对肌阵挛性抽搐的精确发作，对皮质活动进行平均，以评估与肌阵挛相关的皮质磁场。在所有患者中，最早峰值的估计产生源定位于对侧中央前回。从电流方向判断，在3例皮质反射性肌阵挛患者和1例可能患有皮质基底节变性的患者中，检测到肌电图放电前的表面正性活动。相比之下，在其余2例患者（Lennox-Gastaut综合征和阿尔茨海默病）中，与肌阵挛性抽搐时间锁定的磁场与中央前皮质的表面负性活动相关。本研究首次将离线抽搐锁定反向平均分析应用于脑磁图，证明了中央前皮质在产生自发性肌阵挛中的重要作用。电磁活动的不同极性很可能反映了中央前区皮质层状结构内不同的激活模式，这是各种类型肌阵挛产生的基础。
