Abstract
Recent advances in brain imaging have contributed to our understanding of the neural activity associated with acupuncture treatment.
In this study, we investigated functional connectivity across longitudinal acupuncture treatments in older patients with knee osteoarthritis (OA).
Over a period of 4 weeks (six treatments), we collected resting state functional magnetic resonance imaging (fMRI) scans from 30 patients before and after their first, third and sixth treatments.
Clinical outcome showed a significantly greater pain subscore on the Knee Injury and Osteoarthritis Outcome
Score (KOOS) (indicative of improvement) with verum acupuncture than with sham acupuncture. Independent component
analysis (ICA) of the resting state fMRI data showed that the right frontoparietal network (rFPN) and the executive
control network (ECN) showed enhanced functional connectivity (FC) with the rostral anterior cingulate cortex/medial prefrontal cortex, a key region in the descending pain modulatory system, in the verum groups as compared to the sham group after treatments.
We also found that the rFPN connectivity with the left insula is (1) significantly
associated with changes in KOOS pain score after treatments, and (2) significantly enhanced after verum acupuncture treatments as compared to sham treatment. Analysis of the acupuncture needle stimulation scan showed that compared
with sham treatment, verum acupuncture activated the left operculum/insula, which also overlaps with findings
observed in resting state analysis. Our results suggest that acupuncture may achieve its therapeutic effect on knee OA
pain by modulating functional connectivity between the rFPN, ECN and the descending pain modulatory pathway.