Modulation of hand motor-related area during motor imagery and motor execution before and after middle 2/5 of the MS6 line scalp acupuncture stimulation: An fMRI study

•Scalp acupuncture (SA) of the middle 2/5 MS6 line stimulates the M1 hand area.•We compared the pre- and post-SA fMRI activation.•We used implicit motor imagery and explicit execution.•SA inhibited the left hand area and released the right hand area.•Results confirms functional specificity of SA effects.

Scalp acupuncture (SA) combines the concept of cerebral cortex organization with the principles of acupuncture. The SA stimulates sections of the cerebral cortex. We studied the functional modulation of the left hand sensorimotor area induced by SA in order to investigate the specificity of the SA-related functional effects of the middle 2/5 of the MS6 line of the left side, which corresponds to the upper limb motor segment of the primary motor area. To this purpose, we compared the pre- and post-SA functional activation patterns during an implicit motor imagery task (handedness decision in which participants simulated rotational hand movements) and an explicit manual motor execution task. Feet and mouth movements, and the fMRI changes in their respective representations were used as control conditions. Only SA on the hand area of the left side (as compared to the mouth and the foot representations which were used as control conditions) exerted a release effect on the right hand area. In addition, an increased activation of the superior parietal lobe was seen, which is involved in movement control and planning. Taken together, these preliminary findings may shed light on the SA effects and confirm a prolonged effect of SA even after cessation of needling stimulation.