CNRS - Laboratoire de Sciences Cognitives et Psycholinguistique, Institute of Cognitive Studies, Ecole Normale Supérieure, Paris, France
I will report findings from structural MRI analyses carried out on the brain images of a population of 32 dyslexic and 32 control children, as well as on separate groups of dyslexic and control children scanned by collaborators. Our analyses bear on gray matter volumes, cortical thickness, sulcal configurations (of the sylvian fissure and the central sulcus), dimensions and asymmetry of the planum temporale and of Heschl's gyrus, and the micro-structure of the arcuate fasciculus. I will also highlight all the effects published in the dyslexia literature that we have failed to replicate on the way to our results. I will then reflect on the limitations of most published studies, on the conditions necessary to produce replicable results, and on the importance of oft-overlooked variables such as age, sex, SES and IQ.