Neural systems of second language reading are shaped by native language

Abstract

Reading in a second language (L2) is a complex task that entails an interaction between L2 and the native language (L1). To study the underlying mechanisms, we used functional magnetic resonance imaging (fMRI) to visualize Chinese-English bilinguals' brain activity in phonological processing of logographic Chinese and alphabetic English, two written languages with a sharp contrast in phonology and orthography. In Experiment 1, we found that phonological processing of Chinese characters recruits a neural system involving left middle frontal and posterior parietal gyri, cortical regions that are known to contribute to spatial information representation, spatial working memory, and coordination of cognitive resources as a central executive system. We assume that the peak activation of this system is relevant to the unique feature of Chinese that a logographic character has a square configuration that maps onto a monosyllabic unit of speech. Equally important, when our bilingual subjects performed a phonological task on English words, this neural system was most active, whereas brain areas mediating English monolinguals' fine-grained phonemic analysis, as demonstrated by Experiment 2, were only weakly activated. This suggests that our bilingual subjects were applying their L1 system to L2 reading and that the lack of letter-to-sound conversion rules in Chinese led Chinese readers to being less capable of processing English by recourse to an analytic reading system on which English monolinguals rely. Our brain imaging findings lend strongest support to the idea that language experience tunes the cortex.

Writing affects the brain network of reading in Chinese: A functional magnetic resonance imaging study

“…For Chinese, our results converge with results showing greater involvement of bilateral visual-spatial areas and visual-orthographic areas [Bolger et al, 2005;Tan et al, 2005a]. Previous research has also found greater involvement for Chinese reading in a dorsal posterior region of the left inferior frontal gyrus bordering on the precentral gyrus (BA 6/9) [Bolger et al, 2005;Tan et al, 2003Tan et al, , 2005a. In our study, we observed activation during character reading near this same ''Chinese region,'' at the left dorsal inferior frontal gyrus (BA9).…”

“…Among the common neural mechanisms, the left temporo-occipital cortex and left inferior parietal lobule (IPL) are involved in both languages for orthographic analysis and conversion between orthography and phonology/semantics, respectively [Bolger et al, 2005;Booth et al, 2006;Tan et al, 2003]. Among the distinctive mechanisms, right temporo-occipital cortex and bilateral superior parietal lobules are more involved in Chinese than English, presumably due to the complex holistic visual-spatial analysis required by Chinese characters [Cao et al, 2010;Tan et al, 2005a].…”

Reading depends on writing, in Chinese

“…Our motor memory hypothesis is supported by recent neuroimaging studies that found that written Chinese character recognition is critically mediated by the posterior portion of the left middle frontal gyrus, a region just anterior to the premotor cortex (24,33,34). In addition, functional connectivity analyses of neural pathways involved in language processing indicated that reading in Chinese recruits a neural circuit linking Broca's area in the prefrontal cortex and the supplementary motor area, whereas reading in alphabetic (Western) scripts recruits a neural circuit connecting Broca's area and Wernicke's area (35).…”

Arithmetic processing in the brain shaped by cultures

“…For example, the strong involvement of visuopremotor association in NCS may be related to the experience of reading Chinese characters (15,28). A Chinese character is composed of strokes and subcharacters that are packed into a square configuration, possessing a high, nonlinear visual complexity.…”