Objective    To assess the reproducibility of brain activation by functional MR imaging during electroacupuncture stimulation at PC6 (neiguan).     Methods    Six healthy adult volunteers participated in three identical scan sessions during different interval time. Each scan session consists of two functional tasks

an electroacupuncture stimulation (2 Hz) at PC6 and a control task of simple finger tapping. The reproducibility of brain responses was analyzed in terms of the overlap ratio of active volume within session

s and the ICC of active signal intensity in ROIs.     Results    The R

overlap

of the simple finger tapping task (34.24±9.49) was significantly higher than that of the electroacupuncture stimulation task (13.23±14.21). The range of ICC of ROIs in the simple finger tapping task (0.69-0.80) was significantly higher than that of the electroacupuncture stimulation task (0.18-0.68). The results above showed that the reliability of brain activation in the finger tapping task group was higher than that in the electroacupuncture stimulation task group. The active intensity of ROIs in the simple finger tapping task was significantly higher than that in the electroacupuncture stimulation task

indicating the signal to noise ratio of brain activation in the finger tapping task group was higher than that in the electroacupuncture stimulation task group.     Conclusion    In contrast to the relatively reliable activation evoked by the simple finger tapping task

the activation evoked by electroacupuncture stimulation task was much more variable. The main possible reason is that the relatively low signal to noise ratio of brain activation on fMRI and low sensitivity caused the lower reproducibility of electroacupuncture stimulation task. The group analysis in combination with the individual functional data may be utilized to improve the reproducibility of fMRI evoked by electroacupuncture stimulation at PC6 (neiguan).