Immediate and sustained effects of acupuncture on the default mode network.

Objective: Functional magnetic resonance imaging (fMRI) techniques were conducted to investigate the immediate and sustained effects of acupuncture, as well as its impact on the functional connectivity (FC) within the default mode network (DMN) and the external FC.

Methods: Thirty healthy participants received acupuncture needle stimulation at Baihui (GV20) and Yintang (GV29), and underwent resting-state fMRI scans in three phases: pre-needle insertion, during needle retention, and post-needle removal. Each phase lasted for 20 minutes.

Results: In terms of the within-network connectivity of the DMN, post-needle removal scans showed a decrease in FC between the medial prefrontal cortex (mPFC) and the angular gyrus (ANG) compared to pre-needle insertion scans. The FC analysis from seed points to whole-brain voxels showed the following changes: compared to pre-needle insertion scans, acupuncture needle insertion increased the FC between the posterior cingulate cortex/precuneus (PCC/PCU) and Cerebellum_8_L, acupuncture needle withdrawal increased the FC between the PCC/PCU and Cerebellum_8_L; acupuncture needle insertion decreased the FC between ANG and Frontal_Sup_Medial_L, and acupuncture needle withdrawal decreased the FC between ANG and Frontal_Sup_Medial_L.

Conclusions: These results suggested that acupuncture has an impact on the DMN, and acupuncture exhibits sustained effects, not just immediate effects.