Motion illusion activates the visual motion area of the brain: a near-infrared spectroscopy (NIRS) study.

Near-infrared spectroscopy (NIRS) enables noninvasive measurement of concentration changes of oxy- and deoxy-hemoglobin. The present study investigated cerebral representations of motion illusion by NIRS and examined several experimental procedures to determine an efficient procedure that can shorten the experimental time. We compared hemodynamic responses to figures with and without motion illusion. The number of repetitions of the tasks in the experiments and other factors were also examined. Results showed significant responses around area MT/V5 to the motion illusion from the analyses of three cycles (blocks) of presentation of illusion induction stimulus. These findings indicate that motion illusion can be detected by NIRS, and we propose a concise and efficient procedure for NIRS.