The cognitive and neural bases of letter and sound knowledge in reading

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The printed word is an immensely valuable human innovation. It allows a language user to record their thoughts and ideas, and to convey them to other individuals who are not immediately present. Nevertheless, fluent reading requires readers to bring together multiple types of perceptual information and mental knowledge in order process a written text. The present proposal examines a fundamental element of reading: rapidly merging the visual form of language - orthography - with knowledge of the spoken form of language - phonology. We theorize that this audio-visual (A-V) integration process represents a fundamental building block of reading, setting the stage for effective reading acquisition in school-age children and efficient visual word recognition in skilled readers. This Discovery Grant will fund Dr. Marc Joanisse and his research team in the Language, Reading and Cognitive Neuroscience Laboratory at the University of Western Ontario. We propose a multi-modal experimental approach in which we will study the brain bases of reading using both event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI). In a series of experiments we will examine letter-sound processing in groups of typical reading adults and in school-age children of varying ages. While the primary focus is on reading in English, an alphabetic language, we will also investigate these processes in reading Chinese, a logographic script that contains very few phonetic cues. The results will seek to uncover the rapid and automatic integration of visual and written language in both children and adults. They will allow us to isolate neural markers of reading-specific A-V integration in both adults and children; address whether such markers are unique to written language; specify whether they are universal or occur only for alphabetic languages; and identify how these neural markers are related to different aspects of skilled reading and reading development. The results will also have far-reaching implications for the improved diagnosis and treatment of dyslexia and reading disorders following brain injury.