Spatiotemporal Brain Activities on Reading Hiragana Words

Abstract

The authors recorded nineteen-channel event-related potentials (ERPs) during recognition of one type of Japanese character; Hiragana (one type of phonetic characters). By field-sequential stereoscopic 3D display with liquid crystal shutter, a word and a non-word were simultaneously and independently presented to the left (right) and the right (left) eyes, respectively. Each word consists of three Hiragana characters. Three subjects were instructed to press a button after they understood the meaning of the visual stimuli after 3000 ms poststimulus. Equivalent current dipole source localization (ECDL) with three unconstrained ECD was applied to the ERPs. The ECDs were localized to the Wernicke's area at around 600ms. The latter ECD for one left-handed subject was localized at the Wernicke's homologue. After that ECDs were localized to the prefrontal area, the superior frontal gyrus and the middle frontal gyrus. Then at around 800ms, the ECDs were localized to the Broca's area and after that ECDs were localized again to the Wernicke's area and then to Broca's area.