Objective: To characterize the areas of the brain activated by acupuncture in myofascial pain patients.

Design: We will use functional magnetic resonance imaging (fMRI) to investigate the brain regions involved in acupuncture stimulation.

Random, single blind, placebo controlled, clinical trial of acupuncture on myofascial pain patients Patients will be recruited over one year from the UCSF Center for Orofacial Pain. Each functional run consists of 5 minutes, starting with 1-minute baseline and two 1-minute stimulations, the interval between the two stimuli will be 1 minute.

Two functional runs will be performed on each subject in the order of: one run for baseline (no acupuncture) and one run for manual acupuncture. During the experiment, acupuncture needle manipulation will be performed at Large Intestine 4 (LI4, Hegu) on the left hand. Subjects will initiate a painful stimulus consisting of 6 minutes of chewing gum.

Analysis of Data: See statistical analysis of Cho et. al. 2002 study. Results will show if acupuncture does or does not produce fMRI signal increases or decreases in the anterior cingulated cortex, as well as the thalmus. The results will indicate what brain networks are involved during acupuncture stimulation. The results will suggest that specific brain mechanisms may be recruited during acupuncture.