Objective      To determine the analgesia effect in different sensitive constitution and investigate its underlying central nerve modulating mechanism.       Methods      Forty-five healthy volunteers were recruited and divided into 3 typical groups according to Traditional Chinese Medicine theory on constitution

that is

insensitive group

normal group and sensitive group

with 15 cases in each group. Pressure pain threshold (PPT)  was measured in every group before and after a

cupuncture at Zusanli point (ST36). Then paired t test was used to compare the effect of analgesia among the 3 groups. Two weeks later

resting-state BOLD fMRI scanning was carried out by using a gradient-echo echo-planar imaging sequence before and after acupuncture at ST36. All the fMRI data were analyzed by the method of amplitude of low frequency fluctuation (ALFF). Paired t-test was used to analyze the data acquired before and after acupuncture.       Results      Compared the PPT before and after acupuncture

normal group and sensitive group had obvious statistical significance (

P

<

0.05). Compared with the image before acupuncture

the insensitive group showed significant decreased ALFF values in the left fusiform gyrus and left inferior temporal gyrus. No increased ALFF was found in this group. The normal group had significantly increased ALFF values in the bilateral cerebellum posterior lobe

brainstem

limbic lobe

left inferior temporal gyrus

and right caudate

and significantly decreased ALFF values in the left postcentralgyrus

left precentral gyrus

and bilateral occipital lobes. The ALFF values in the sensitive group were increased mainly in the bilateral cerebellum posterior lobe

fusiform gyrus

inferior temporal gyrus

basal ganglia

frontal lobe

anterior cingutate

right supramarginal gyrus

right supplementary motor area

and left insular lobe

while the regions with decreased ALFF values were the left middle temporal gyrus

left postcentral gyrus

posterior cingutate

and bilateral occipital lobes.       Conclusion      Person with different sensitive constitution has different acupuncture analgesia effect. The underlying central nervous modulating mechanism may be due to acupuncture causing response of different brain areas.