title: Modulation of the visual word retrieval system in writing: a functional MRI study on the Japanese orthographies.
abstract: We used functional magnetic resonance imaging (fMRI) to examine whether the act of writing involves different neuropsychological mechanisms between the two script systems of the Japanese language: kanji (ideogram) and kana (phonogram). The main experiments employed a 2 x 2 factorial design that comprised writing-to-dictation and visual mental recall for kanji and kana. For both scripts, the actual writing produced a widespread fronto-parietal activation in the left hemisphere. Especially, writing of kanji activated the left posteroinferior temporal cortex (lPITC), whereas that of kana also yielded a trend of activation in the same area. Mental recall for both scripts activated similarly the left parietotemporal regions including the lPITC. The writing versus mental recall comparison revealed greater activations in the left sensorimotor areas and right cerebellum. The kanji versus kana comparison showed increased responses in the left prefrontal and anterior cingulate areas. Especially, the lPITC showed a significant task-by-script interaction. Two additional control tasks, repetition (REP) and semantic judgment (SJ), activated the bilateral perisylvian areas, but enhanced the lPITC response only weakly. These results suggest that writing of the ideographic and phonographic scripts, although using the largely same cortical regions, each modulates the visual word-retrieval system according to their graphic features. Furthermore, comparisons with two additional tasks indicate that the activity of the lPITC increases especially in expressive language operations regardless of sensory modalities of the input stimulus.
authors.affiliation: Kyoto University, Japan.
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Nakamura
authors.forename: Manabu
authors.initials: M
authors.lastname: Honda
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hirano
authors.forename: Tatsuhide
authors.initials: T
authors.lastname: Oga
authors.forename: Nobukatsu
authors.initials: N
authors.lastname: Sawamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Hanakawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inoue
authors.forename: Jin
authors.initials: J
authors.lastname: Ito
authors.forename: Tetsu
authors.initials: T
authors.lastname: Matsuda
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibasaki
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D002531:Cerebellum / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology; D006236:Handwriting; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging; D011939:Mental Recall / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D012660:Semantics