Authors: Pedro M. Paz-Alonso, Myriam Oliver, Garikoitz Lerma-Usabiaga, et al..
Publication: NeuroImage: Clinical . Volume 20, Pages 433-447, 2018 | DOI: 10.1016/j.nicl.2018.08.018
- Regional hypoactivation in dyslexic readers specifically associated with phonological, orthographic and semantic processes
- Stronger functional connectivity for dyslexic versus control readers among regional hypoactivated nodes
- Increased subcortico-cortical connectivity among regions showing regional reading deficits
The present study aims to characterize left hemisphere regional hypoactivation in readers with dyslexia for the main processes involved in successful reading: phonological, orthographic and semantic. Forty-one participants performed a demanding reading task during MRI scanning. Results showed that readers with dyslexia exhibited hypoactivation associated with phonological processing in parietal regions; with orthographic processing in parietal regions, Broca’s area, ventral occipitotemporal cortex and thalamus; and with semantic processing in angular gyrus and hippocampus. Stronger functional connectivity was observed for readers with dyslexia than for control readers 1) between the thalamus and the inferior parietal cortex/ventral occipitotemporal cortex during pseudoword reading; and, 2) between the hippocampus and the pars opercularis during word reading. These findings constitute the strongest evidence to date for the interplay between regional hypoactivation and functional connectivity in the main processes supporting reading in dyslexia.