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.
CLINICAL TRIAL NUMBER: NCT01079390.