A preliminary fMRI study of acupuncture with healthy volunteers

Objective To observe the cortical functioning of healthy volunteers during acupuncture as a way of exploring acupuncture′s neural mechanisms. Methods Twenty healthy volunteers received acupuncture applied to the left hegu and waiguan acupoints while their cortical activity was examined using blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI). Brain activation, especially of the regions related to motor function, were observed and analyzed. Results Acupuncture applied to the left hegu and waiguan acupoints was observed to significantly activate the left middle frontal gyrus and the inferior frontal gyrus, with many activated regions in the left insula and a few in the left cerebellum, the left precentral gyrus, the left postcentral gyrus, the left inferior parietal lobule, the left medial frontal gyrus, the left precuneus, the left anterior cingulate gyrus and the left claustrum. The right side of the brain was excited mainly in the right middle frontal gyrus and the right medial frontal gyrus. The right inferior parietal lobule and the right precentral gyrus were also activated to some extent. There was slight activation of the right middle temporal gyrus, the right superior temporal gyrus, the right insula, the right inferior frontal gyrus and the right postcentral gyrus. The negatively activated regions were mainly located on both sides of the limbic lobe, including the hippocampus, the parahippocampal gyrus and the cingulate gyrus. The left superior temporal gyrus, the left middle temporal gyrus and the right middle frontal gyrus also had small negative activation zones. Conclusions In brain regions associated with motor function, in addition to partial activation of the contralateral primary sensorimotor area, acupuncture at these two points clearly generates bilateral activation of secondary motor areas with some activation in the ipsilateral cerebellum. This may serve as a neuropathological basis for acupuncture treatment of motor dysfunction. BOLD-fMRI imaging displays the neural effects of acupuncture in an intuitive way. It can be a useful technique for further study of the neural effects of acupuncture on pathological conditions. Key words: Acupuncture; Hegu; Waiguan; Functional magnetic resonance imaging