Deqi(needle sensation)

is closely related to clinical therapeutic effect of acupuncture in the treatment of different clinical conditions.In the present paper

the authors summarized various components or concepts of Deqi mainly in the fo-reign studies collected from Pubmed database.At present

foreign researches about Deqi mainly include 1) the subjects' subjective qualitative and quantitative descriptions about Deqi

2) correlation between acupuncture stimulation induced Deqi and clinical therapeutic effects

and 3) responses of different brain regions or the connectivity of brain network shown by functional magnetic resonance imaging(fMRI) during Deqi by needling different acupoints.According to the current commonly used 6 questionnaires

aching

tingling

numbness

heaviness

dull pain

throbbing

and deep pressure sensation are the most frequently seen components of Deqi of acupuncture stimulation.The factors influencing Deqi are psychological state

personal previous experience and cultural background.Regarding the degree of Deqi and clinical effects or outcomes

the conclusions are controversial.Results of fMRI analysis shows that in spite of extensive deactivation of the limbic system has been found in many studies

and the connectivity of the intrinsic brain functional networks is increased during acupuncture-induced Deqi

the significance of activation or deactivation of some brain regions remains unclear

and the related mechanisms need to be studied further.No matter activation or dea-ctivation of different brain regions during Deqi

the most important issue is the relationship between Deqi and clinical therapeutic effects.Further studies are definitely needed.