The Visual Word Form Area: evidence from an fMRI study of implicit processing of Chinese characters.

A notable controversy in neurolinguistics is whether there is a particular brain area specialized for visual word recognition within the visual ventral stream. We investigated this question via implicit processing of Chinese characters. Implicit processing of four types of stimuli--real characters, pseudo characters, artificial characters, and checkerboard--in two different sizes, were compared in 14 normal participants using functional MRI (fMRI) with a size judgment task. The results showed that when the three character types were contrasted to one another, there was significantly greater activation in the left middle fusiform gyrus during real and pseudo character processing compared to artificial characters. Moreover, individual analysis revealed that the coordinates were consistent with the Visual Word Form Area (VWFA) reported for alphabetic scripts. Results also showed a consistent activation in the left middle frontal gyrus (BA 9) for real and pseudo characters. The relation between this region and the VWFA in Characters processing still needs further investigation.

Arithmetic processing in the brain shaped by cultures.

The universal use of Arabic numbers in mathematics raises a question whether these digits are processed the same way in people speaking various languages, such as Chinese and English, which reflect differences in Eastern and Western cultures. Using functional MRI, we demonstrated a differential cortical representation of numbers between native Chinese and English speakers. Contrasting to native English speakers, who largely employ a language process that relies on the left perisylvian cortices for mental calculation such as a simple addition task, native Chinese speakers, instead, engage a visuo-premotor association network for the same task. Whereas in both groups the inferior parietal cortex was activated by a task for numerical quantity comparison, functional MRI connectivity analyses revealed a functional distinction between Chinese and English groups among the brain networks involved in the task. Our results further indicate that the different biological encoding of numbers may be shaped by visual reading experience during language acquisition and other cultural factors such as mathematics learning strategies and education systems, which cannot be explained completely by the differences in languages per se.

Mapping cortical areas associated with Chinese word processing using functional magnetic resonance imaging.

OBJECTIVES: To identify the cortical areas engaged during Chinese word processing using functional magnetic resonance imaging (fMRI) and to examine the reliability and reproducibility of fMRI for localization of functional areas in the human brain. METHODS: FMRI data were collected on 8 young, right-handed, native Chinese speakers during performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems (1.5 T GE Signa Horizon and 1.5 T Siemens Vision). A cross correlation analysis was used to statistically generate the activation map. RESULTS: Broca's area, Wernicke's area, bilateral extrastriate, and ventral temporal cortex were significantly activated during both the synonym and homophone activities. There was essentially no difference between results acquired on two different MRI systems. CONCLUSIONS: FMRI can be used for localizing cortical areas critical to Chinese language processing in the human brain. The results are reliable and well reproducible across different clinical MRI systems.