Testing for dual brain processing routes in reading: a direct contrast of chinese character and pinyin reading using FMRI

Abstract

Chinese offers a unique tool for testing the effects of word form on language processing during reading. The processes of letter-mediated grapheme-to-phoneme translation and phonemic assembly (assembled phonology) critical for reading and spelling in any alphabetic orthography are largely absent when reading nonalphabetic Chinese characters. In contrast, script-to-sound translation based on the script as a whole (addressed phonology) is absent when reading the Chinese alphabetic sound symbols known as pinyin, for which the script-to-sound translation is based exclusively on assembled phonology. The present study aims to contrast patterns of brain activity associated with the different cognitive mechanisms needed for reading the two scripts. fMRI was used with a block design involving a phonological and lexical task in which subjects were asked to decide whether visually presented, paired Chinese characters or pinyin "sounded like" a word. Results demonstrate that reading Chinese characters and pinyin activate a common brain network including the inferior frontal, middle, and inferior temporal gyri, the inferior and superior parietal lobules, and the extrastriate areas. However, some regions show relatively greater activation for either pinyin or Chinese reading. Reading pinyin led to a greater activation in the inferior parietal cortex bilaterally, the precuneus, and the anterior middle temporal gyrus. In contrast, activation in the left fusiform gyrus, the bilateral cuneus, the posterior middle temporal, the right inferior frontal gyrus, and the bilateral superior frontal gyrus were greater for nonalphabetic Chinese reading. We conclude that both alphabetic and nonalphabetic scripts activate a common brain network for reading. Overall, there are no differences in terms of hemispheric specialization between alphabetic and nonalphabetic scripts. However, differences in language surface form appear to determine relative activation in other regions. Some of these regions (e.g., the inferior parietal cortex for pinyin and fusiform gyrus for Chinese characters) are candidate regions for specialized processes associated with reading via predominantly assembled (pinyin) or addressed (Chinese character) procedures.