The role of the cerebral cortex in acupuncture modulation of the somesthetic afferent.

It is known from previous work that acupuncture stimulation modifies the somesthetic afferent to different extends depending on the acupoint studied. In this study, somatosensory evoked potentials of 21 healthy volunteers are recorded. When acupoint LI-4 (Hoku) is stimulated, it produces noticeable modifications, with a significant increase of latency and decrease of amplitude of the peaks which reflect the primary cortical afferent. Comparison of these results with the absence of changes when the experiment is repeated by stimulating a non-acupuncture point, ensures that the effects observed depend on the special quality of the acupuncture point stimulated and not on the mere repetitive stimulation on the skin.