ABSTRACT

Neurobiological evidence fo r underlying reorganization o f language-processing systems. Age-related changes were observed in the lateral and anterior-posterior distribution of ERP differences to com prehended versus unknown words. A t 13 to 17 months ERP differences to com prehended versus unknown words were bilateral and were distributed widely over anterior and posterior regions. By 20 months these effects were limited to temporal and parietal regions of the left hemisphere. These results raise the hypothesis that a reorganiza­ tion of language-relevant neural systems occurs sometim e between 13 and 20 months. It is our working hypothesis that the neurophysiological changes that give rise to the ERP effects reported here are at least in part linked to the remarkable changes in early lexical development that typically occur between 13 and 20 months.