Phonological priming in visual word recognition for English words: An event related functional MRI study
AUTHORS
ABSTRACT
Functional magnetic resonance imaging (fMRI) was used to explore the nature of the mappings between orthography, phonology, and semantics in reading English words. Stimulus pairs were arranged in a priming paradigm with lexical decision to understand the neural correlates of phonological processes. Homophonic targets varied in the regularity of the mapping from spelling to sound (e.g., feetfeat, bare-bear). There were three main findings. First, the results revealed that the left middle temporal gyrus (BA 21) showed increased neural activity for phonologically primed irregular pairs consistent with increased semantic involvement in making lexical decisions when the mapping between orthography and phonology is made difficult. Second, the left supramarginal gyrus (BA 40) was associated with reduced neural activity for phonologically-identical pairs with regular spelling to sound correspondences, when the mapping between orthography and phonology is made easy. Third, the visual association cortex including the left fusiform gyrus (BA 37) showed more activation in the homophone pairs compared to the unrelated pairs and more activation for pseudoword targets compared to word targets, suggesting that this region may have been involved in a spelling check on lexical decisions. These three findings show how phonological priming effects on behaviour can result from a complex interaction of several processing phases involving both increases and decreases of activity