Oxygenated hemoglobin levels in the prefrontal cortex, measured using near-infrared spectroscopy, during a 1-minute session of electroacupuncture or a 1-minute rest, averaged over a 5-round stimulus cycle. Data from 8 healthy subjects. Data are presented as the mean ± standard deviation. MM-mm, millimole millimeter; sec, second; Ch, Channel;. Color images are available online.