Modulatory effects of acupuncture on resting-state networks: a functional MRI study combining independent component analysis and multivariate Granger causality analysis.

PURPOSE

To investigate acupuncture specificity by exploring causal relationships of brain networks following acupuncture at GB40 (Qiuxu), with the acupoint KI3 (Taixi) as a control (belonging to the same nerve segment but different meridians).

MATERIALS AND METHODS

Needling at acupoints GB40 and KI3 was performed in 12 subjects separately. The specific coherent patterns, resting-state networks (RSNs), were retrieved by independent component analysis (ICA) from functional magnetic resonance imaging (fMRI) data of resting state and post-acupuncture resting states, respectively. Then multivariate Granger causality analysis (mGCA) was applied to evaluate the effective connectivity within and among the detected RSNs-default model, memory, executive, auditory, and motor brain networks.

RESULTS

Following acupuncture at GB40, the strength of causal connectivity between the superior temporal gyrus (STG) and anterior insula was enhanced, while the connection strength between the STG and postcentral gyrus increased following acupuncture at KI3. Additionally, the causal influences within the auditory network increased following acupuncture at GB40, in comparison with the executive network following acupuncture at KI3.

CONCLUSION

The current study demonstrates that acupuncture at different acupoints could exert different modulatory effects on RSNs. Our findings may help to understand the neurophysiological mechanisms underlying acupuncture specificity.