A study of the brain functional network of Deqi via acupuncturing stimulation at BL40 by rs-fMRI

Acupuncture is a therapeutic treatment defined as the insertion of needles into the body at specific points (i.e., acupoints). The acupuncture sensation of Deqi is an important component of acupuncture, but the functional brain responses of Deqi have not been entirely supported by the results of functional magnetic resonance imaging (fMRI) studies. The aims of this study were to test the conditions that would generate a Deqi sensation and to investigate the effect of Deqi and the response of acupuncture at different depths and intensities on brain fMRI blood oxygen level-dependent (BOLD) signals.

Healthy subjects (n=16) completed two resting-state fMRI (rs-fMRI) scans, once during shallow needling (2 mm) and once during deep needling (10-20 mm) pseudorandomly, at the acupoint BL40.

When undergoing shallow needling, 16 subjects had a mild stabbing pain sensation, and no one had a composite Deqi sensation; when undergoing deep needling, 14 subjects had a composite Deqi sensation, and only 2 subjects had a sharp pain feeling. Composite deep needling of Deqi sensation modulated neural activity at multiple levels of the brain and cerebellum, decreased functional connectivity in the default mode networks (DMN) and the pain matrix networks, and increased connectivity in the right posterior cerebellar lobe, left parahippocampal gyrus, thalamus, and supplementary motor area (P<0.05, false discovery rate [FDR]<0.05). When subjects underwent shallow needling, the brain network increased functional connectivity in the right side (precentral gyrus, superior frontal gyrus, cerebellar tonsil) and both side thalami; moreover, the right side of the medial prefrontal cortex had a decreased functional connection (P<0.05, FDR<0.05).

The hemodynamic response of deep needling of Deqi sensation hypothesis whereby deep needing could affect a variety of deep tissues and never fibers was supported as acupuncture modulates the limbic-paralimbic-neocortical network to produce its Deqi effects. The similarity of LPNN and DMN suggests that deep needing may mobilize an important intrinsic brain network for its multiple modulation effects.