Neural strategies for reading Japanese and Chinese sentences: a cross-linguistic fMRI study of character-decoding and morphosyntax.

Japanese and Chinese share virtually identical morphographic characters invented in ancient China. Whereas modern Chinese retained the original morphographic functionality of these characters (hanzi), modern Japanese utilizes these characters (kanji) as complex syllabograms. This divergence provides a unique opportunity to systematically investigate brain strategies for sentence reading in Japanese-Chinese bi-literates. Accordingly, we investigated brain activation associated with Japanese and Chinese reading in 14 native Japanese speakers literate in Mandarin and 14 native Mandarin speakers literate in Japanese using functional magnetic resonance imaging performed on a 3T system. The activation pattern exhibited clearly distinct features specific for each language. Regardless of the subject's native language literacy, Chinese reading activated an area significantly larger than Japanese reading, suggesting that brain processes involved in Chinese reading were much more complex than Japanese reading. Significant recruitment of corresponding cortical areas in the right hemisphere with Chinese reading was also apparent. The activation patterns associated with Japanese reading by native Japanese literates was highly consistent with previous reports, and included the left inferior frontal gyrus (IFG), left posterior temporal lobe (PTL), and left ventral premotor cortex (PMv). The activation pattern associated with Chinese reading by native Chinese literates was also highly consistent with previous reports, namely the left IFG, left PTL, left PMv, left anterior temporal lobe (ATL), and bilateral parieto occipital lobes (LPOL). The activation pattern associated with Chinese reading by native Japanese literates was virtually identical to that by native Chinese literates, whereas the activation pattern associated with Japanese reading by native Chinese literates was signified by additional activation of LPOL compared to that by native Japanese literate. The study indicated that IFG and PTL are universal language areas, while PMv is the area for decoding complex syllabograms. LPOL is the "Chinese language area," while ATL is essential for languages with analytic morphosyntax.