[Observation on the functional characteristics of cortical somatosensory area during the advance of the propagated sensation along meridians].

It is still not clear what role is played by cortical somatosensory system during the advance of propagated sensation along meridians (PSM). In this paper the short-latent somatosensory evoked potential (SLSEP) was taken as an indication to observe the characteristics of functional activity in cortical somatosensory area I (SI) during the advance of PSM. The observation was preformed on 10 subjects with marked PSM, which were clear and kept stable. Sixteen subjects without SPM were taken as control. Electrical stimulation was delivered to the acupoint Jiaxi (GB43) or Hegu (LI4). The SLSEP were recorded simultaneously from 3 scalp points corresponding to the representative areas of foot, arm and face contralateral to the stimulated side. The results are shown as follows. When Jiaxi was stimulated, the amplitudes of SLSEP component C2 (P45-N55) from above three scalp points in subjects without PSC were 0.85 +/- 0.17, 0.51 +/- 0.11 and 0.31 +/- 0.07 microv respectively. The amplitude was largest in the foot representative area, but attenuated successively in arm and face areas and a stair-shaped distribution was thus formed. During stimulating the acupoint Hegu (LI4) the amplitude of SLSEP component C2 (P25-N55) from the representative area of arm in subjects without PSM was larger than that from the representative areas of foot and face, and a distribution with high-medium and low-bilateral character was shaped. However, no matter whether stimulating Jiaxi or Hegu the amplitude of SLSEP C2 in subjects with marked PSM was nearly the same from three scalp points.(ABSTRACT TRUNCATED AT 250 WORDS)