Differences in the neural basis of Chinese and English reading UCL-China Research Festival - Audio

Introduction: Previous functional imaging studies comparing Chinese and English reading have reported that a left middle frontal region is more activated by Chinese reading and the left superior temporal cortex is more activated by English reading (Tan et al. 2001; 2003). We investigated this finding and its interpretation by conducting a functional magnetic resonance imaging (fMRI) study of reading in China and England using monolingual adolescents who spoke Mandarin or English respectively. Our paradigm compared activation for semantic decision on written stimuli (words or characters) as well as on pictures of objects so that we could determine whether or not the previously reported effects were specific to written stimuli.

Methods: The paradigm involved 4 different stimulus conditions: semantic decisions on (1) written object names and (2) pictures of objects; and perceptual decisions on (3) pictures of meaningless non-objects and (4) meaningless Greek/Korean letters. Written stimuli were presented in the known language (i.e. characters in Chinese and words in English). The pictures were identical in the Chinese and English versions of the study. In each condition, three stimuli were presented, one above (the target) and two below (the choices). Using the right hand, participants were instructed to indicate with a left or right button press whether the target matched the left or right choice. For example, when the stimuli were “anchor” (target), “ship” and “truck”(choices), participants made a left button press to indicate that “anchor” is more closely associated with a “ship” than “truck”. Stimulus presentation parameters were identical for perceptual decisions but here the task was to indicate whether the left or right choice was perceptually identical to the target above.

Data were acquired from the whole brain using 1.5T MRI scanners at Wellcome Trust Centre for Neuroimaging, UCL and Institute of Linguistics at XuZhou Normal University. Participants were 13 English adolescents (age 13-16) and 10 Chinese adolescents (age 13-16) with no history of reading impairment. Data analysis was carried out with SPM5 software package and effects of interest were based on correct responses only.

Results and Conclusions Behaviourally, performance and response times did not differ across groups. In reading, consistent with previous findings, Chinese subjects showed significantly more activation in the left middle frontal region while English subjects showed significantly more activation in the left posterior superior temporal cortex. However, we also observed significantly greater left middle frontal activation in the Chinese group during semantic decisions on pictures. Therefore, the effect in the left middle frontal region is not specific to reading. Next, we explored inter-subject variability within each group. This led to the observation that differences between the Chinese and English groups were driven by a subgroup of English subjects. This suggests that the differences observed here at the group level were more likely to be due to individual differences in education or other cognitive skills than to writing system or ethnicity alone.