Electroacupuncture modulates cortical functional connectivity and network topology in healthy adults: an fNIRS study

Acupuncture has shown clinical benefits in post-stroke rehabilitation, yet its central neural mechanisms remain incompletely understood. In particular, how cortical activation, inter-regional functional connectivity, and brain network topology are modulated during electroacupuncture stimulation has not been systematically characterised. This study aimed to investigate the central effects of verum electroacupuncture (VE) applied to the non-dominant hand in healthy adults. In a randomized, crossover design, functional near-infrared spectroscopy (fNIRS) data were collected from 24 participants during VE and sham electroacupuncture (SE) sessions. Cortical activation was assessed using a general linear model (GLM), functional connectivity (FC) was analysed using lagged cross-correlation, and brain network topology was examined using graph-theoretical metrics. No significant differences in cortical activation were observed between VE and SE. During the needles retention phase, VE significantly reduced functional connectivity between R-MPFC and right primary somatosensory cortex (R-PSC), and between middle MPFC and R-PSC. Graph-theoretical analysis revealed decreased clustering coefficient and increased small-worldness under VE. These findings suggest that VE may optimise brain networks through an connectivity-topology mechanism. Brain networks shifted from excessive localisation toward higher integration. This study establishes a baseline central response profile in healthy individuals and provides theoretical support for the application of electroacupuncture in post-stroke upper-limb rehabilitation. Trial registration: ITMCTR, TRN: ITMCTR2025000595, Registration date: 19 March 2025.