To study

through blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI)

the cerebral activated areas evoked by electro-acupuncturing (EA) the right Hegu point (LI4) or non-acupoint points on the face

and through comparing their similarities and differences

to speculate on the specific cerebral areas activated by stimulating LI4

for exploring the mechanism of its effect in potential clinical application. EA was applied at volunteers’ right LI4 (of 9 subjects in the LI4 group) and facial non-acupoint points (of 5 subjects in the control group)

and whole brain 3-dimensional T1 anatomical imaging of high resolution 1 × 1 × 1 mm3 used was performed with clustered stimulatory mode adopted by BOLD fMRI. Pretreatment and statistical t-test were conducted on the data by SPM2 software

then the statistical parameters were superimposed to the 3-dimensional anatomical imaging. Data from 3 testees of the 9 subjects in the LI4 group were given up eventually because they were unfit to the demand due to different causes such as movement of patients’ location or machinery factors. Statistical analysis showed that signal activation or deactivation was found in multiple cerebral areas in 6 subjects of LI4 group and 5 subjects of the control group (P<0.01). In the LI4 group

the areas which showed signal activation were: midline nuclear group of thalamus

left supra marginal gyrus

left supra temporal gyrus

right precuneous lobe

bilateral temporal pole

left precentral gyrus and left cerebellum; those which showed signal deactivation were: bilateral hippocampus

parahippocampal gyrus

amygdala body area

rostral side/audal side of cingulate gyrus

prefrontal lobe and occipital lobe as well as left infratemporal gyrus. In the control group

areas which showed signal activation were: bilateral frontal lobe

postcentral gyrus

Reil’s island lobe

primary somato-sensory cortex

cingulate gyrus

superior temporal gyrus

occipital cuneiform gyrus and/or precuneus gyrus and right brainstem; and the area that showed deactivation was left median frontal lobe. The effects of EA LI4 in regulating cerebral activities could be displayed and recorded through BOLD fMRI

the distribution of signally deactivated area evoked by EA LI4 was similar to the known distribution of anatomical orientation of pain in brain

and closely related to the anatomic structure of limbic system

which areas are possibly the acupuncture analgesic effect’s cerebral regulating area. Furthermore

activated portion of left central anterior gyrus

which represent the movement of oral facial muscles

and the activated portion of cerebellum are possibly related with the effect of using EA LI4 in treating facial palsy and facial muscle spasm. As for the mechanism of signal deactivation of cerebral activities exhibited in the present study that is unable to be elucidated

it awaits for further research.