There is research suggesting that acupuncture can produce measurable changes in the brain. The limbic system is a region of the brain involved in regulating the endocrine system and the autonomic nervous system. Research appearing in Human Brain Mapping (2000; 9:13–25) evaluated 13 subjects (five males and eight females). The subjects received acupuncture in the hand at the Hegu point. The treatment produced a reduction in fMRI signals in the limbic system and in subcortical areas of the brain.

Another study, appearing in the journal NeuroImage (2001; 14:60–66), examined the effect of acupuncture using positron emission tomography (PET) scans. A PET scan is an imaging test that shows how organs and tissues inside the body are functioning. It can measure blood flow, oxygen utilization, and glucose metabolism, reflecting metabolic changes occurring at the cellular level. During a PET scan, the subject is injected with a radiotracer (a small dose of a radioactive compound). The scanner detects and records the energy released by the tracer and generates computerized images of the body.

In this study, 13 subjects between the ages of 21 and 32 received PET scans before acupuncture treatment and again 25 minutes after treatment. Activation was observed in areas of the brain associated with chronic pain processing, including the left anterior cingulate cortex, the insulae bilaterally, the cerebellum bilaterally, the left superior frontal gyrus, and the right medial and inferior frontal gyri.

Additional research, reported in the December 1999 issue of Medical Tribune, evaluated brain activity in 12 subjects and the effect acupuncture had on pain perception. Seven subjects received acupuncture, and five received electro-acupuncture. Brain activity related to pain stimulation decreased in all subjects receiving electro-acupuncture and in four of the seven subjects receiving acupuncture without electrical stimulation.

Pain reduction from acupuncture has also been shown to last for up to six months in patients suffering from migraine headaches.