Shimojo M, Svensson P, Arendt-Nielsen L, Chen A C
Humain Brain Mapping and Cortical Imaging Laboratory, Center for Sensory-Motor Interaction, Aalborg University, Denmark.
Brain Topogr. 2000 Fall;13(1):43-58. doi: 10.1023/a:1007834319135.
The differential effects of painful stimulation of skin vs. muscle on the cerebral electrophysiology have been poorly described. This study examined the somatosensory evoked potentials (SEPs) and the associated dipole models of non-painful and graded painful electrical stimulation applied to the skin and muscle in 20 healthy subjects. With the psychophysical stimulus-response functions determined, the skin stimulation showed a steeper slope than muscle stimulation. For both types of stimulation, the SEPs indicated a similar temporo-spatial activation sequence: F4/N90-P4/P95, Fc2/N135, Cz/P250, Cz/P300, and Cz/N460. The SEP amplitudes increased significantly with the stimulus intensities in these components. The peak SEP latencies of skin stimulation were in general shorter than that of muscle stimulation. The SEP amplitudes to skin stimulation were significantly larger than those caused by muscle stimulation at every stimulus intensity level, except the early mid-latency component. In this case, muscle stimulation caused higher amplitudes over the contralateral parietal-frontal sites. For both types of stimulation, the topographic maps were quite similar. Equivalent dipole modeling revealed identical site parameters (<1.0 cm) between skin and muscle stimulation. However, the electrical skin stimulation did not correlate with the pain intensity. Pain intensity, in contrast, was uniquely associated with the Cz/P250 amplitudes for the muscle stimulation. It is concluded that non-nociceptive and nociceptive electrical stimuli applied to skin and muscle are processed in the common cerebral areas, but exhibit differential SEP effects.
皮肤与肌肉的疼痛刺激对大脑电生理的不同影响鲜有描述。本研究检测了20名健康受试者在接受施加于皮肤和肌肉的非疼痛及分级疼痛电刺激时的体感诱发电位（SEP）及相关偶极子模型。在确定了心理物理刺激-反应函数后，皮肤刺激显示出比肌肉刺激更陡的斜率。对于两种类型的刺激，SEP均显示出相似的颞-空间激活序列：F4/N90-P4/P95、Fc2/N135、Cz/P250、Cz/P300和Cz/N460。这些成分中的SEP波幅随刺激强度显著增加。皮肤刺激的SEP峰潜伏期总体上短于肌肉刺激。除早期中潜伏期成分外，在每个刺激强度水平下，皮肤刺激的SEP波幅均显著大于肌肉刺激所引起的波幅。在这种情况下，肌肉刺激在对侧顶叶-额叶部位引起更高的波幅。对于两种类型的刺激，地形图非常相似。等效偶极子模型显示皮肤和肌肉刺激之间的部位参数相同（<1.0 cm）。然而，皮肤电刺激与疼痛强度无关。相比之下，疼痛强度仅与肌肉刺激的Cz/P250波幅相关。结论是，施加于皮肤和肌肉的非伤害性和伤害性电刺激在共同的脑区进行处理，但表现出不同的SEP效应。
