Processing of Chinese characters and pure tones in literate and illiterate subjects: An auditory fMRI study

Using functional magnetic resonance imaging (fMRI) or positron emission tomography (PET), much knowledge has been gained in understanding how the brain is activated during controlled experiments of language tasks in educated healthy subjects and in uneducated healthy subjects. While previous studies have compared performance in visual tasks, few data adopted auditory tasks, especially in Chinese-speaking individuals. In this study, we used fMRI to investigate brain activations in processing characters by auditory tasks in 26 Chinese subjects (13 illiterates and 13 literates). After comparison of the language stimuli to the control stimuli, we observed: activation regions in the literate group involve the left superior temporal gyrus (BA22), right inferior frontal gyrus (BA47), left middle frontal gyrus (BA9), right middle temporal gyrus (BA21), dorsal anterior cingulate (BA32), and left middle frontal gyrus (BA6); in the illiterate group, activations occur in the right middle temporal gyrus (BA21), left superior temporal gyrus (BA22) and left inferior frontal gyrus (BA47). Conclusively, the left middle frontal gyrus (BA9) is strongly related to Chinese character processing and this modulated brain plasticity may be acquired by literacy and education.