The increased inter-brain neural synchronization in prefrontal cortex between simulated patient and acupuncturist during acupuncture stimulation: Evidence from functional near-infrared spectroscopy hyperscanning.

The patient-acupuncturist interaction was a critical influencing factor for acupuncture effects but its mechanism remains unclear. This study aimed to examine the inter-brain mechanism of patient-acupuncturist dyad during acupuncture stimulation in a naturalistic clinical setting. Seventy healthy subjects (simulated "patients") were randomly assigned to two groups and received verum acupuncture group or sham acupuncture by one acupuncturist. Functional near-infrared spectroscopy hyperscanning was used to simultaneously record the neural responses of "patient"-acupuncturist dyad during acupuncture stimulation in each group. The results showed that inter-brain neural synchronization (INS) in the prefrontal cortex (PFC) of "patient"-acupuncturist dyad was significantly increased during verum but not sham acupuncture stimuli, and positively correlated with the needling sensations of "patients." Granger causality analysis demonstrated that there were no significant differences in INS direction between the "patient" and the acupuncturist. This study identified the increase of INS between "patient" and acupuncturist, and suggested that PFC was important to the interaction of "patient"-acupuncturist dyad.