Objective To observe the relationship between the analgesic effect of balance acupuncture and functional changes in brain in patients with migraine without aura.Methods A total of 40 cases of migraine without aura were equally randomized into a headache-acupoint group and a sham-acupoint group.When acupuncture given

a filiform needle was inserted into the headache-acupoint(the midpoint of the depression region anterior to the juncture of the first and second metatarsal bones on the dorsum of the foot)or the sham point(the midpoint of the depression region anterior to the juncture site between the 3 rd and4 th metatarsal joints of the dorsum of the foot)about 25—40 mm deep and manipulated for a while till the patient experienced feelings of electric shock and numbness

then withdrawn immediately.The treatment was conducted once daily for 4 weeks.The visual analogue scale(VAS)was used to evaluate the severity of pain

and the regional homogeneity(ReHo)analysis of resting state functional magnetic resonance imaging(fMRI)was used to assess changes of the spontaneous brain activity.Results After acupuncture

the analgesic effect of headache-acupoint was better than that of the sham-acupoint in both intervention stage and the follow-up stage(P<0.05)

and was also stronger in the intervention stage than in the follow-up stage(P<0.05).There was no significant difference in the analgesic effect between the intervention stage and the follow-up stage in the sham-acupoint group(P>0.05).Compared with pre-intervention

4-weeks' intervention at the headache-acupoint showed an increase of ReHo values in the anterior cingulate gyrus

anterior central gyrus

superior orbital frontal gyrus

insula

inferior lobule

left anterior cingulate gyrus

ventral lateral nucleus and ventral posteromedial nucleus of the thalamus

pontine nucleus

cerebellar tonsils and orbital frontal inferior gyrus of the brain(P<0.05)

and a decrease of ReHo values in the right brain bridge

central posterior gyrus

posterior cingulate gyrus

left central anterior gyrus

posterolateral nucleus of thalamus

and hippocampus(P<0.05)

separately.In the sham-acupoint group

the ReHo value was increased in the right tongue gyrus

the left anterior lobe

the anterior cingulate gyrus and the lower occipital gyrus of the brain(P<0.05)

and reduced in the left ventral posterolateral nucleus of the thalamus

separately(P<0.05).Conclusion Balance acupuncture stimulation of headache acupoint has an analgesic effect in migraine patients without aura

which may be related to its effect in regulating resting state brain function of the limbic-system-dominated multiple brain regions.