CHARLESTOWN, MASSACHUSETTS. Although acupuncture has been successfully used for thousands of years in China it is still viewed with considerable skepticism by many Western medical practitioners. One of the main stumbling blocks to greater acceptance is the lack of understanding of how it works. This may all change now with the publication of a seminal report by researchers at the Harvard Medical School. The researchers used functional magnetic resonance imaging (fMRI) to investigate how acupuncture affects brain activity in normal subjects. Thirteen healthy volunteers (ages 27 to 52 years) were involved in the study. They were seated in the MRI scanner and after relaxing had an acupuncture needle inserted in the LI 4 or Hegu point (located on the hand between the thumb and forefinger). The needle was left at rest for two minutes followed by two periods of manipulation (twirling) with a four-minute rest period in between. The researchers noted a highly significant correlation between brain activity and needle manipulation. Needle manipulation caused a pronounced calming of activity (decreased signal intensity) in the deep structures (amygdala, hippocampus, hypothalamus, etc.) of the brain accompanied by an increased signal intensity in the somatosensory cortex. They conclude that "modulation of this neuronal network could constitute the initiating steps by which acupuncture regulates multiple physiological systems and achieves diverse therapeutic effect". [62 references]
Hui, Kathleen, K.S., et al. Acupuncture modulates the limbic system and subcortical gray structures of the human brain: evidence from fMRI studies in normal subjects. Human Brain Mapping, Vol. 9, 2000, pp. 13-25