The human brain response to acupuncture on same-meridian acupoints: evidence from an fMRI study

Stimulation of acupuncture points (acupoints) located on meridians has been proven to activate specific areas of the human brain, as evidenced by functional imaging studies. To date, the specificity of acupoints located on different meridians has been investigated with functional magnetic resonance image (fMRI). The present fMRI study explored the effects of stimulating 4 acupoints on 2 different meridians for the purpose of researching the characteristic response of acupoints on the same meridian.

The acupoints studied were LR3 (Taichong) and LR6 (Zhongdu), which belong to the Liver meridian of Foot-Jueyin; ST36 (Zusanli) and ST43 (Xiangu), which belong to the Stomach meridian of Foot-Yangming; and 2 nearby sham acupoints. Fifty-three (53) healthy right-handed subjects were divided randomly into 6 groups. Each group only received acupuncture at one acupoint. All the acupoints in this study were stimulated only on the right side of the subject's body. Through analysis of fMRI data from all subjects, we obtained the activation patterns in the central nervous system (CNS) evoked by acupuncture.

In contrast to the CNS activation by sham acupoint, the results showed that all 4 real acupoints under consideration had the common effect of activating 2 specific areas of the brain: the bilateral primary somatosensory area and the ipsilateral cerebellum. Acupuncture stimulation of both acupoints LR3 and LR6 evoked activation at the ipsilateral superior parietal lobe (BA7). Acupuncture stimulation of both acupoints ST36 and ST43 evoked activation at the ipsilateral middle frontal gyrus (BA10).

These results suggest that different acupoints on the same meridian may activate certain similar areas of the brain. In addition, acupoints that are commonly used in clinical practice might modulate a greater extent of cortical areas than uncommonly used acupoints.