Asymmetry Of Reading Related White Matters In Chinese Native Speakers

Typical reading not only involves the function of gray matter brain regions, but also needs specific white matter tracts to communicate and transfer information between different gray matter areas. In this paper, we explored the asymmetry of three major white matter fiber tracts between left and right brain among Chinese native speakers with high angular resolution diffusion imaging method which to certain extent could resolve the problem of crossing fibers in human brain. These three tracts were inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF) and arcuate fasciculus (AF), which involved in the orthographic, phonological and semantic processing during Chinese reading, respectively. Present evidences were mainly obtained from researches on English native speakers. As there are many linguistic differences between Chinese and English, these proofs could not be generalized to Chinese native speakers directly. In this paper, we measured the property of these fiber tracts with a macroscopic index and a microscopic index-tract volume and quantitative anisotropy. In terms of tract volume, our results showed that there was variance in the asymmetry of ILF:four out of seven subjects had leftward bilateral representation, while the remaining had rightward bilateral representation. The differences were significant in these two situations. All participants had leftward bilateral representation of the volume of IFOF and AF, and the differences were also significant. As for normalized quantitative anisotropy, there was significant difference only between left and right IFOF, while the other two were insignificant. Then we discussed possible reasons of above results and the advantages of high angular resolution diffusion imaging method. This research provides some insights for characteristics of these three fiber tracts in Chinese native speakers, and also the difference between English and Chinese reading process.