Abstract
A region in the left lateral fusiform cortex has been identified to play an important role in processing written scripts. There is evidence that this region is selectively sensitive to visual word form information, and thus has been labeled as the Visual Word Form Area (VWFA). Here we investigated the neural plasticity of this region and addressed the question of whether the specialization of this region for processing written scripts can only be formed during an individual's developmental stage. Chinese adults who were illiterate but otherwise neurologically and intellectually normal were recruited in this study. They provide a fresh blank slate to examine if extensive reading training can reshape the functional selectivity in the mid-fusiform region. The illiterate subjects were taught to read Chinese characters in regularly scheduled Chinese classes. In block-design fMRI experiments conducted before and at different stages of their training, subjects viewed Chinese characters as well as images of faces and line drawing objects. Before training, subjects showed expected activation to faces and line-drawing objects, but none of the subjects showed significant activation to Chinese characters in the mid-fusiform region. However, after moderate training (e.g., learned 100 characters or more), most of these illiterate subjects showed enhanced activity to Chinese characters in the presumed VWFA region, usually slightly lateral to the left fusiform face area. Thus the results show that the adult brain is highly adaptive and certain regions can be transformed to acquire new functional selectivity. In addition, the fact that training adult illiterate subjects lead to the same anatomical region to become sensitive to written scripts compared to people who acquired reading skills in their normal developmental stages suggests that the VWFA must have intrinsic properties that are especially suited for the processing of visual written scripts.