Abstract
It is well-known that language processing is lateralized in left cerebral hemispheres while spatial processing in right. We investigated whether simple object perceptual process was lateralized or not with behavioral tasks while monitoring activation of occipital cortex using Near Infrared spectroscopy (NIRS). Object words, object line drawings and meaningless line drawings were prepared for stimuli. A stimulus was presented firstly at the center and then successively either in left or right visual hemi-field (LVF, RVF). Subjects judged whether the two drawings/words were the same or not. In word and meaningless object judgment, oxy-hemoglobin concentration increased in broader area in both hemispheres with LVF than RVF. In line drawing judgment, more activation was observed in both hemispheres with RVF than LVF. This result indicates that cortical function starts lateralizing at an early stage of visual perception.
