• Approximately 2,000 years ago, the pre-eminent acupuncture text, Huangdi Neijing (Yellow Emperor's Classic on Internal Medicine), was written. In it, acupuncture was described as a means of letting out excess qi or blood by making holes in the body along certain pathways, called jingluo (meridians).

• For some of these meridians, it was advised to acupuncture in such a way as to let out the blood but not the qi; for others, to let out the qi, but not the blood.

• Many diseases were thought to enter the body through the skin, and then penetrate inward through muscle, internal organs, and, if not cured in timely fashion, to the marrow of the bone.

• By inserting a needle to the appropriate depth-to correspond with the degree of disease penetration-the disease could be let out.

Regulation of Qi

• The flow of qi through the meridians, just like the flow of water through a stream, could be blocked off by an obstruction-a dam across the waterway.

• In the streams, this might be a fallen tree or a mud slide; in humans, it might be caused by something striking the body, the influence of bad weather, or ingestion of improper foods.

• When a stream is blocked, it floods above the blockage, and below the blockage it dries up. If one goes to the point of blockage and clears it away, then the stream can resume its natural course. In a like manner, if the qi in the meridian becomes blocked, the condition of the body becomes disordered; if one could remove the blockage from the flow of qi within a meridian, the natural flow could be restored.

MODERN VIEWS

• Diseases are understood to be caused by microorganisms, metabolic failures, changes in DNA structure or signaling, or breakdown of the immune system.

• Some of these disorders are resolved by the cellular functions that are designed for healing, while others become chronic diseases because the pathological factors involved have either defeated the body's normalizing mechanisms or because something else has weakened the body's responses to the point that they are ineffective. For example, poor nutrition, unhealthy habits, and high stress can weaken the responses to disease.

• When the human body was finally described in terms of cells, biochemicals, and specific structures, diseases and injuries are resolved by a complex set of responses; the responses are coordinated by several signaling systems.

• The signaling systems mainly involve peptides and other small biochemicals that are released at one site, travel to other sites, interact with cells, and stimulate various biologically programmed responses;

• Modern studies have revealed that acupuncture stimulates one or more of the signaling systems, which can, under certain circumstances, increase the rate of healing response. This may be sufficient to cure a disease, or it might only reduce its impact (alleviate some symptoms). These findings can explain most of the clinical effects of acupuncture therapy

• According to current understanding, the primary signaling system affected by acupuncture is the nervous system, which not only transmits signals along the nerves that comprise it, but also emits a variety of biochemicals that influence other cells of the body. The nervous system, with over 30 peptides involved in transmitting signals, is connected to the hormonal system via the adrenal gland, and it makes connections to every cell and system of the body.

• According to TCM, one of the key elements of a successful acupuncture treatment is having the person who is being treated experience the "needling sensation." This sensation may vary with the treatment, but it has been described as a numbness, tingling, warmth, or other experience that is not simple pain. Sometimes the needling sensation is experienced as propagating from the point of needling to another part of the body. This is called "getting qi." In this case, the needle seems to get pulled by the body, and this may be understood in modern terms as the result of muscle responses secondary to the local nervous system interaction.

• According to this interpretation, acupuncture is seen as a stimulus directed to certain responsive parts of the nervous system, producing the needling sensation and setting off a biochemical cascade which enhances healing. Needling at certain points may stimulate a "global" healing response that can affect many diseases; needling at other points may affect only one of the signaling systems.

Evidence from neuroimaging studies

• Interest in investigating acupuncture with various imaging techniques have been growing since the mid 1990s.

• The development of imaging techniques, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), have opened a ‘window’ into the brain that allows us to gain an appreciation of the anatomy and physiological function involved during acupuncture in humans and animals.


New findings of the correlation between acupoints and corresponding brain cortices using functional MRI

PNAS March 3, 1998 vol. 95 no. 5 2670-2673

• A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI).
• The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI.
• Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI.
• The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data

The vision-related acupoints BL67 (VA1), BL66 (VA2), BL65 (VA3), and BL60 (VA8)

Result:

Experiments with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation.

We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed.

Conclusion:

The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature