Brain imaging of acupuncture: comparing superficial with deep needling

The difference between superficial and deep needling at acupuncture points has yet to be mapped with functional magnetic resonance imaging (fMRI). Using a 3T MRI, echo planar imaging data were acquired for 17 right-handed healthy volunteer participants. Two fMRI scans of acupuncture needling were taken in random order in a block design, one for superficial and one for deep needling on the right hand at the acupuncture point LI-4 (Hegu), with the participant blind to the order. For both scans needle stimulation was used. Brain image analysis tools were used to explore within-group and between-group differences in the blood oxygen level dependent (BOLD) responses. The study demonstrated marked similarities in BOLD signal responses between superficial and deep needling, with no significant differences in either activations (increases in BOLD signal) or deactivations (decreases in BOLD signal) above the voxel Z score of 2.3 with corrected cluster significance of P=0.05. For both types of needling, deactivations predominated over activations. These fMRI data suggest that acupuncture needle stimulation at two different depths of needling, superficial and deep, do not elicit significantly different BOLD responses. This data is consistent with the equivalent therapeutic outcomes that are claimed by proponents of Japanese and Chinese styles of acupuncture that utilise superficial and deep needling, respectively.