Oliver, M. 1 , Paz-Alonso, P. M. 1 , Lerma, G. 1 , Caballero, C. 1 , Quiñones, I. 1 , Suarez-Coalla, M. P. 4 , Duñabeitia, J. A. 1 , Cuetos, F. 4 & Carreiras, M. . 1, 2, 3
1 BCBL. Basque Center on Cognition, Brain and Language. Donostia-San Sebastián, Spain
2 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
3 Departmento de Lengua Vasca y Comunicación, UPV/EHU, Bilbao, Spain
4 Departamento de Psicología, Universidad de Oviedo, Spain
Readers with dyslexia exhibit less stable orthography-phonology mappings. Reading in transparent orthographies relies on small grain size linguistic units (grapheme-phoneme). Thus, variations in orthographic consistency of small-unit patterns may compromise phonological decoding in transparent orthographies and present additional difficulties for dyslexic readers. This fMRI study was aimed at investigating the neural correlates of pseudohomophone and orthographic consistency effects in Spanish readers with dyslexia and matched controls. At the scanner participants were presented with four stimuli types: regular words, inconsistent words that have specific pronunciation rules (ingeniero), regular pseudowords, and homophones or non-words derived from misspells in inconsistent words (ajencia). Behavioral results revealed a higher proportion of naming errors for pseudowords and pseudohomophones in dyslexic compared to control readers. Regional analyses revealed group by condition interactions for the pseudohomophone effect (Pseudohomophone-Pseudoword) in left angular gyrus and hippocampus, and for the orthographic consistency effect (Pseudohomophone-Inconsistent_words) in left broca, ventro-occipito-temporal cortex and parietal cortex. Across all these regional interactions stronger activation was observed in controls relative to dyslexic readers. Convergent results were also observed in functional connectivity analysis. Our data revealed a less specialized and more disconnected neural patterns for orthographic consistency and phonology in dyslexic readers, associated with their reading difficulties.