Neural initialization of audiovisual integration in prereaders at varying risk for developmental dyslexia

Learning letter‐speech sound correspondences is a major step in reading acquisition and is severely impaired in children with dyslexia. Up to now, it remains largely unknown how quickly neural networks adopt specific functions during audiovisual integration of linguistic information when prereading children learn letter‐speech sound correspondences. Here, we simulated the process of learning letter‐speech sound correspondences in 20 prereading children (6.13–7.17 years) at varying risk for dyslexia by training artificial letter‐speech sound correspondences within a single experimental session. Subsequently, we acquired simultaneously event‐related potentials (ERP) and functional magnetic resonance imaging (fMRI) scans during implicit audiovisual presentation of trained and untrained pairs. Audiovisual integration of trained pairs correlated with individual learning rates in right superior temporal, left inferior temporal, and bilateral parietal areas and with phonological awareness in left temporal areas. In correspondence, a differential left‐lateralized parietooccipitotemporal ERP at 400 ms for trained pairs correlated with learning achievement and familial risk. Finally, a late (650 ms) posterior negativity indicating audiovisual congruency of trained pairs was associated with increased fMRI activation in the left occipital cortex. Taken together, a short (