De qi, a threshold of the stimulus intensity, elicits the specific response of acupoints and intrinsic change of human brain to acupuncture.

Objectives.  De qi is the subjective constellation of sensations perceived by the acupuncturists and patients as described in several literatures, but the absence of quantitative evaluation methods in de qi restricts the use of acupuncture treatment widely in the world. In the present study, we tried to investigate the intrinsic property of de qi is and how evaluate it quantitatively. Methods. 30 healthy adult volunteers were determined to investigate intrinsic changes in the human body after acupuncture with de qi. Results. Acupuncture treatment with de qi apparently increased acupoint blood flow, tissue displacement, and the amplitude of myoelectricity after de qi on acupoints. Furthermore, acupuncture treatment induced fMRI signal increase/decrease in different brain regions although no significant change in electroencephalography. Interpretation. The intrinsic change of the subjects representing the specific response of acupoints and human brain to acupuncture indicated that de qi might be evaluated quantitatively by those above aspects, which facilitated the confirmation in validity and propagation of this treatment modality widely in the world.