Investigation of acupoint specificity by whole brain functional connectivity analysis from fMRI data

Previous neuroimaging studies on acupuncture have primarily adopted functional connectivity analysis associated with one or a few preselected brain regions. Few have investigated how these brain regions interacted at the whole brain level. In this study, we sought to investigate the acupoint specificity by exploring the whole brain functional connectivity analysis on the post-stimulus resting brain modulated by acupuncture at acupoint PC6, with the same meridian acupoint PC7 and different meridian acupoint GB37. We divided the whole brain into 90 regions and analyzed functional connectivity for each condition. Then we identified statistically significant differences in functional correlations throughout the entire brain following acupuncture at PC6 in comparison with PC7 as well as GB37. For direct comparisons, increased correlations for PC6 compared to PC7 were primarily between the prefrontal regions and the limbic/paralimbic and subcortical regions, whereas decreased correlations were mainly between the parietal regions and the limbic/paralimbic and subcortical regions. On the other hand, increased correlations for PC6 compared to GB37 were primarily between the prefrontal regions and somatosensory regions, whereas decreased correlations were mainly related with the occipital regions. Our findings demonstrated that acupuncture at different acupoints may exert heterogeneous modulatory effects on the post-stimulus resting brain, providing new evidences for the relatively function-oriented specificity of acupuncture effects.