Figure 1.

Time course of acupuncture needling. The acupuncture needle was inserted and the sensitivity of the subject to manipulation was pre-tested and adjusted to tolerance prior to starting functional MRI scanning. The needle remained at rest for 2 min after the start of MRI scanning before bidirectional rotation at 1 Hz for 2 min. The needle was not manipulated for 3 min, then manipulation was repeated for 2 min, followed by a third period of rest for 1min. The needle was removed after MRI scanning was complete. Data analysis compared the blood oxygenation level–dependent (BOLD) MRI signal intensity of the two needling periods with the three rest periods, with the first minute of scanning excluded from analysis to allow for MRI signal equilibration.