The amygdala may be a key brain region linking two systems that combine to produce acupuncture’s antinociceptive effects in chronic low back pain (cLBP). American researchers investigated the effects of acupuncture on resting state functional connectivity (rsFC) of the periaqueductal gray (PAG) and ventral tegmental area (VTA) in patients with cLBP. Seventy-nine cLBP patients were assigned to four weeks of real or sham acupuncture. Resting state functional magnetic resonance imaging data were collected before the first and after the last treatment. Real acupuncture involved a modified standardised acupuncture protocol based on cLBP clinical trials (Yaoyangguan DU-3, bilateral Shenshu BL-23, bilateral Weizhong BL-40, bilateral Taixi KI-3, plus ashi points on the lower back and legs). Sham acupuncture was applied at non-acupoints points using a non-penetrating sham device. Remission of pain bothersomeness was observed in all treatment groups after four weeks, with greater pain relief after real acupuncture compared to sham. Real acupuncture resulted in increased rsFC between the VTA/PAG and the amygdala, and this increased was associated with decreased pain bothersomeness. The authors conclude that acupuncture may simultaneously modulate the rsFC of key regions in the descending pain modulation (PAG) and reward systems (VTA), and that the amygdala may be a key node linking the two systems to produce antinociceptive effects.

Acupuncture Treatment Modulates the Connectivity of Key Regions of the Descending Pain Modulation and Reward Systems in Patients with Chronic Low Back Pain. J Clin Med. 2020 Jun 3;9(6):1719.