Modulation effect of acupuncture treatment on chronic neck and shoulder pain in female patients: Evidence from periaqueductal gray-based functional connectivity

Aims Chronic neck and shoulder pain (CNSP) is a common neurological disorder, which females are more likely to suffer from. The periaqueductal gray (PAG) plays a key role in the descending modulation of pain. This study aimed to investigate altered PAG-based functional connectivity (FC) in female patients with CNSP related to healthy controls (HCs) and the effect of acupuncture for female patients with CNSP using PAG-based FC biomarkers. Methods PAG-based FC value was calculated based on resting-state functional images and then compared between patients with CNSP at pre-acupuncture, post-acupuncture, and HCs. Then, correlational analyses were performed to examine the relationships between increased PAG-based FC strength and improved clinical parameters in patients after acupuncture treatment. Results Before acupuncture treatment, compared to HCs, patients with CSNP showed altered PAG-based FC with widely distributed brain regions, including the left medial superior frontal gyrus, bilateral posterior insula (pIns), and cingulate gyrus. After treatment, patients with CNSP exhibited specially improved PAG-pIns FC compared to that before treatment, and no significant difference was observed in the increased PAG-pIns FC strength between HCs and patients with CNSP after treatment. Furthermore, pain catastrophizing reduction was significantly correlated with the increased PAG-pIns FC strength in patients after treatment. Conclusion The effect of acupuncture treatment may relate to the increased PAG-pIns FC, which significantly correlated with pain catastrophizing reduction after treatment. These findings shed important mechanistic information on the role of therapeutic approaches in treating chronic neck and shoulder pain.