The Plasticity Of Visual Word Selectivity In VWFA While Learning A New Writing System

Visual Word Form Area(VWFA) is a cortical region in the left occipitotemporal cortex, which seem as a fundmental functional region in words/character processing, and show significiant selectivity in representation of visually presented words. Converging evidence from electrophysiological and functional neuroimaging studies has demonstrated that the selectivity of the VWFA largely originates from extensive experience with visual words. However, it is still less clear in understanding neural mechanism underlying this plasticity. Present studies used the functional magnetic resonance imaging (fMRI) to investigated, within-subject reproducibility of selectivity in VWFA and the neural mechanisms of functional plastic changes of this area.Using the fMRI technique, study 1 tracked the within subject reproducibility of selectivity in VWFA between scanning sessions separated by 1 year. Reproducibility was very high for both of Chinese-character-sensitive VWFA (cVWFA) and English-word-sensitive VWFA (eVWFA) between scanning sessions separated by nearly 1 year.The mean distance between peak voxels of the same area localized by using different functional runs was less than 3mm,and functional reproducibility, as expressed by the stability of T-values across sessions was high in between-session comparisons as well.Study 2 Used a longitudinal research paradigm to further investigated the neural substrates of the plasticity of visual word selectivity in VWFA during classroom training of Arabic in subjects. We found that VWFA response to the Arabic words was significantly increased after training, while This classroom training-induced change in neural activities was significantly slower in contrast with the artificial stimuli training used in most previous studies, and changed in stage form; at the pre-training stage,subjects showed significant selectivity in VWFA for Arabic words than face in location judgement task, and the mean distance between peak voxels of the same area localized by using different functional runs was about 3.3mm.In conclusion,1) the findings demonstrate, within subjects, high-level category-specific visual areas can be localized robustly across scanning sessions, which suggest the functional localizer used in previous studies (and our study 2) is stable;2) Our study clearly illuminates that the plasticity of the VWFA can be shaped by classroom training, but much more slower than short-term artificial stimuli training, indicate the neural substrates of plasticity induced by classroom training maybe different from short-term artificial stimuli training.3) In addition to reading experience, other factors such as the original function of VWFA and the reading neural network shaped by native language learning may also contributed to the placity of new morphological selectivity.