Study on brain network function of the specific connection between Hégǔ (合谷LI4) and the facial-oral area

Objective This study was designed to observe the effect of electroacupuncture at Hegǔ (合谷LI4), or Houxī (后溪SI3) or Waiguān (外关TE5) acupoints on the function of the brain regions of a healthy human, and to explore the neural information mechanism of a specific connection between LI4 and the facial-oral area from the point of view of the brain function connection network. A further objective was to enrich knowledge of the specific connection between the body surface and the meridian route, and the specificity of acupoint effects. Methods A total of 30 healthy volunteers were randomly assigned to LI4, SI3, and TE5 groups. The members of each group were stimulated with electroacupuncture, and their heads were scanned using fMRI. DPARSFA 2.4 and REST 1.8 software were used for data preprocessing and statistical analysis. The paired t-test was used within group and the double sample t-test was used for two-group comparisons. Results In healthy people, left LI4 with electroacupuncture mainly caused a decrease of the functional connection of the right orofacial motor area of the brain, which remained decreased after removing the needle. When LI4 was compared with SI3 and TE5, LI4 caused a more significant decline in the functional connection of the right side of the brain during acupuncture. Conclusions Acupuncture at LI4 has a significant effect on the function of the face- and mouth-related areas in the brain, and there is a continuous effect. It is suggested that LI4 and the face and mouth have a specific relationship in the brain, which is most obvious during acupuncture.