Zhang S, et al. - Researchers performed a comparison of the clinical effects between acupuncture at the contralateral and ipsilateral Tiaokou (ST 38) point in patients with unilateral shoulder pain. In addition, they explored how contralateral- and ipsilateral-acupuncture modulates the regional homogeneity (ReHo) of patients with chronic shoulder pain (CSP). Results indicated that the stimulation given at contralateral and ipsilateral acupoints exhibit different clinical effects and brain mechanisms in patients with CSP. Anterior cingulate cortex (ACC) might play a direct role in the regulation of brain by the contralateral acupuncture at ST 38 in patients with shoulder pain. However, in the mechanism of acupuncture at ipsilateral ST 38, the pathway of brainstem-thalamus-cortex might be working.