The neural substrates of verum acupuncture compared to non-penetrating placebo needle: An fMRI study

Acupuncture, an ancient East Asian therapeutic technique, is currently emerging as an important modality in complementary and alternative medicine around the world. Several studies have provided useful information regarding neurophysiological mechanisms of acupuncture in human brain activation. We explored brain activation using functional magnetic resonance imaging (fMRI) and compared verum acupuncture to placebo needles. Two fMRI scans were taken in random order in a block design, one for verum acupuncture and one for non-penetrating placebo needles at the motor function-implicated acupoint LR2, on the left foot, in 10 healthy volunteers. We calculated the contrast that subtracted the blood oxygen level-dependent (BOLD) responses between the verum and sham acupuncture. Verum acupuncture stimulation elicited significant activation in both motor function-related brain areas, including the caudate, claustrum, and cerebellum, and limbic-related structures, such as the medial frontal gyrus, the cingulate gyrus, and the fusiform gyrus. These findings suggest that acupuncture not only elicited acupoint-implicated brain activation, but also modulated the affective components of the pain matrix. The current investigation of the specific pattern of the brain activation related to genuine acupuncture provides new information regarding the neurobiological basis of acupuncture.