The purpose of this study was to compare the cerebral blood flow changes during several motor imagery tasks. Nine right-handed healthy volunteers participated in this study. The oxygenated hemoglobin concentrations (oxy-Hb) in the right premotor area (PM), supplementary motor area (SMA), and the primary motor cortex (M1) were measured using a 24-channel near-infrared spectroscopy system in the following 4 conditions: a ball rotation task performed with the subject's left hand (LH), motor imagery induced by watching the video footage of a ball rotation task with otherʼs left hand (MIOLH), a task performed with the subject's right hand (RH), and motor imagery induced by mirror visual feedback of the task performed by the right hand (MIMVFRH). The increase in oxy-Hb over baseline levels during MIMVFRH was larger than that during MIOLH (p < 0.01) and RH (p < 0.05) in the SMA. In the PM and M1, oxy-Hb during LH and MIMVFRH showed no significant changes over baseline values. MIOLH showed no significant changes in oxy-Hb in the motor related areas. We conclude that motor imagery induced by mirror visual feedback increases cerebral blood flow in the SMA and PM, in contrast to a task performed without mirror visual feedback.
