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The reading brain from preschoolers to adults: left specialization for letters evidenced by a novel EEG approach| old_uid | 16278 |
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| title | The reading brain from preschoolers to adults: left specialization for letters evidenced by a novel EEG approach |
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| start_date | 2018/09/20 |
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| schedule | 14h |
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| online | no |
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| location_info | Pôle recherche, Amphi A |
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| summary | Reading is a complex skill, acquired only through formal instruction, that depends crucially on left hemispheric (LH) brain structures. In this talk, I will present several experiments in adults and children, as well as in epileptic patients implanted with intracerebral electrodes, focusing on the characteristics of the adult expert reading network, the emergence of this network in children, and the spatial organization of reading processes in the ventral occipito-temporal lobe.
For this, I used a novel approach in EEG, the Fast Periodic Visual Stimulation, where oddball stimuli are inserted periodically (e.g., every 5 items) in streams of rapidly presented (e.g., 10Hz) base stimuli. This paradigm allows to extract and quantify discrimination responses between oddball (for instance, words) and base stimuli (for instance, pseudo-words), in a very short testing time (around 2 minutes) because of its high sensitivity.
In adults, we found clear responses for words in the left OT region, even when inserted in streams of pseudowords, suggesting lexical access. In development, we found LH responses already in kindergarten children, which, importantly, correlated with the children’s letter knowledge. We also examined if and how several methods of learning to read may influence the reliance on the LH for reading. Finally, our intracerebral study in a large group of patients reveals a spatial dissociation between posterior regions that process exclusively letters, and mid-fusiform regions that process words. Contrarily to some strict gradient of processing proposals, we do not find a spatial hierarchy between pre-lexical and lexical processes, but on the contrary they seem to be intermingled in the same mid-fusiform region. |
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| responsibles | Fournier |
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