[The components of somatosensory evoked potentials P250-N350 induced by nervi tibialis posterior stimulation].

The pain components of somatosensory evoked potentials (SEPs) induced by nervi tibialis posterior stimulation were studied by blocking bloodstream of leg in 10 normal adults. The SEPs following the painful stimuli (0.1 msec square wave pulse) of the right ankle were recorded from the parietal median (C'Z) and the reference electrode at earlobe. The pressure of 80 mmHg above the arterial pressure was given to the right calf by sphygmomanometer. The result showed that the P250-N350 components (latency 244.2 +/- 10.1 msec and 344.2 +/- 14.9 msec) of the SEPs persisted and the others disappeared when tactile sensation disappeared but pain existed. It suggested the P250-N350 were the pain potentials of nervi tibialis posterior SEPs.