An fMRI study of neuronal specificity of an acupoint: electroacupuncture stimulation of Yanglingquan (GB34) and its sham point.

The neuronal specificity of acupoints has not been entirely supported by the results of fMRI studies. The objective of this study was to investigate the neuronal specificity of an acupoint with electroacupuncture stimulation (EAS) using functional magnetic resonance imaging (fMRI). Functional MR imaging of the entire brain was performed in 12 normal healthy subjects during EAS of GB34 (Yanglingquan) and its sham point over the left leg in counter-balanced order. Anatomically, both GB34 and its sham point belong to the L5 spinal segment. EAS at the left GB34 specifically activated the right putamen, caudate body, claustrum, thalamus, cerebellum, as well as the left caudate body, ventral lateral thalamus, and cerebellum, all related to motor function. EAS at the sham point of the left GB34 specifically activated the right BA6, BA8, BA40, BA44, thalamus, as well as the left thalamus and cerebellum. Taken together, these findings suggest that EAS at an acupoint and its sham point, in the same spinal segment, induced specific cerebral response patterns. These findings support neuronal specificity of the acupoint studied. EAS at GB34 appears to be more related to motor function than EAS at its sham point, suggesting specificity of the GB34 acupoint. The results of this study provide neurobiological evidence for the existence of acupoint specificity, although further studies are necessary to better understand this phenomenon.