Developmental differences in the brain systems for reading
AUTHORS
ABSTRACT
Functional magnetic resonance imaging (fMRI) was used to examine the distribution of brain activation during four visual word-processing tasks performed by children (9-12 years) and adults (21-31 years). The four tasks were designed to separately emphasize orthographic, phonological, semantic, and syntactic processes. As expected, the adults performed these tasks more efficiently than the children, who were significantly less accurate in their performance. the patterns of brain activation in the two groups suggest that efficient processing of visual word forms in adults results in part from three trends. (1) A shift in activation from multimodal areas (namely, wernicke’s area in children) to activation of unimodal association areas (fusiform cortex in adults). (2) More restricted interactions between cortical areas in adults as the areas involved in linguistic processes become more specialized and efficient. (3) Overlap of areas associated with high accuracy and quick reaction times in adults as word representations become more directly accessible to areas involved in preparing a behavioral response. These trends reflect plasticity in neural processing during maturation, a process that effectively frees resources for processing unfamiliar stimuli as the ability to respond quickly and accurately to familiar stimuli improves.