Motor activity and imagery modulate the body-selective region in the occipital-temporal area: a near-infrared spectroscopy study.

The extrastriate body area (EBA) lies in the occipital-temporal cortex and has been described as a "body-selective" region that responds when viewing other people's bodies. Recently, several studies have reported that EBA is also modulated when the subject moves or imagines moving their own body, even without visual feedback. The present study involved 3 experiments, wherein the first experiment was conducted to examine whether near-infrared spectroscopy (NIRS) could capture any activity in the EBA when viewing images of bodies. The second experiment was designed to elucidate whether this region also responds when the subjects move their own body, and the third to observe whether imagining carrying out a movement would activate EBA. Images of human bodies and chairs were used as the stimuli for the first experiment, simple hand movements carried out by the subject were used for the second and the act of imagining hand movements for the third. Our results confirmed that the region we defined as EBA was clearly activated when the subject viewed images of human bodies, carried out movements of their own body and imagined moving parts of their own body, thus demonstrating the usefulness of NIRS as a new brain imaging method. Moreover, we found a gender-based difference when imagining movement; male subjects showed a greater response than female subjects. This may reflect a gender difference in imagery skills; however, further research is needed to verify this hypothesis.