GRADED SOMATIC AND VISUAL ACUPUNCTURE MODULATES FUNCTIONAL CONNECTIVITY ACROSS BRAIN NETWORKS

Accumulating evidence indicates that stronger acupuncture stimulation is associated with greater clinical benefit, yet the network-level neural substrates of acupuncture dose–response effects remain unclear. This study examined whether graded somatic acupuncture (SA) and visual acupuncture (VA) modulate functional connectivity (FC) across large-scale brain networks.
Twenty-four healthy adults underwent SA and VA at three dose levels (control, low, high) during functional magnetic resonance imaging (fMRI). Stimulation intensity was systematically manipulated by varying rotation angle and frequency, with matched parameters across SA and VA. SA involved needle insertion and rotation at a leg acupoint, whereas VA consisted of viewing prerecorded videos of the same procedures without somatosensory input. A resting-state fMRI scan preceded event-related task fMRI. Task-based FC was estimated using a trial-wise general linear model approach, with regions of interest defined by group independent component analysis of resting-state data and assigned to large-scale brain networks. FC between regions was compared across dose conditions for each modality.
Across both SA and VA, graded stimulation induced widespread, dose-dependent FC changes spanning sensorimotor, salience, visual, and default mode networks. Stimulation (control vs stimulation) and dose (high vs low) contrasts revealed partially overlapping but modality-specific patterns: SA preferentially engaged sensorimotor–salience network interactions, whereas VA primarily modulated visual–default mode network connectivity.
These findings demonstrate that network-level FC analyses capture graded and modality-dependent effects of acupuncture that are not fully reflected in regional activation measures alone, providing a systems-level account of somatic and visual contributions to acupuncture-related brain responses.