Wassermann E M, Fuhr P, Cohen L G, Hallett M
Human Cortical Physiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Neurology. 1991 Nov;41(11):1795-9. doi: 10.1212/wnl.41.11.1795.
We studied the effects of transcranial magnetic stimulation of the motor cortex on ipsilateral upper extremity muscles in six normal men. Stimulation had inhibitory and excitatory effects on the muscles during voluntary activation. Transient inhibition, an ipsilateral silent period (ISP), occurred in all muscles tested, often without any preceding excitatory response. Motor evoked potentials (MEPs) occurred ipsilaterally in the proximal muscles of some subjects. Ipsilateral MEPs and ISPs were delayed relative to the MEPs evoked by the same stimulus in the corresponding contralateral muscles. The excitability of the alpha motoneuron pool, assessed during the period of the ISP by eliciting H-reflexes, showed no change, suggesting that ipsilateral inhibition acts at a level above the alpha motoneuron. Connections from motor cortex to ipsilateral muscles could be via the corpus callosum and contralateral hemisphere or via purely ipsilateral pathways.
我们研究了经颅磁刺激运动皮层对6名正常男性同侧上肢肌肉的影响。在自主激活过程中，刺激对这些肌肉有抑制和兴奋作用。所有受试肌肉均出现短暂抑制，即同侧静息期（ISP），且常常无任何先前的兴奋反应。在一些受试者的近端肌肉中出现了同侧运动诱发电位（MEP）。同侧MEP和ISP相对于相同刺激在相应对侧肌肉中诱发的MEP有所延迟。在ISP期间通过引出H反射评估α运动神经元池的兴奋性，结果显示无变化，这表明同侧抑制作用于α运动神经元以上的水平。从运动皮层到同侧肌肉的连接可能通过胼胝体和对侧半球，或通过纯同侧通路。
