Relations between real-time language processing, cortical thickness and language outcomes in school-aged children

The cognitive neuroscience of language development has typically study how children acquire language knowledge (e.g. phonemes, words or grammatical rules of the language). However, children must also build a cognitive and neural system that can support efficient use of this information for real-time language processing. To address this gap, the present study aimed to identify neural systems supporting real-time word recognition in school-age children (2nd to 4th graders). We investigated the relationships between real-time word recognition and brain structure (cortical thickness and area), focusing on how these links are influenced by age and language ability. Our analysis revealed two key dimensions of word recognition: Activation Rate, the speed at which lexical candidates accrue evidence, and Competition Resolution, the ability to suppress irrelevant candidates. Cortical thickness emerged as a crucial factor, with thinner regions supporting more efficient processing and no relations were found to cortical area Cortical thickness of the ventral brain regions were primarily associated with Activation Rate, while cortical thickness of the dorsal regions were linked to Competition Resolution, with stronger involvement in younger and less skilled children. Individual variability in brain structure was robustly linked to real-time language processing, even after accounting for age and language ability. These findings underscore the importance of cortical thickness in efficient lexical processing and highlight the need for refined behavioral indices in neurocognitive research.