Striatal activity during contextual word learning is influenced by children's reading ability

Abstract

Contextual word learning is a fundamental mechanism for vocabulary acquisition during childhood. In adults, successful inference of word meaning from context is intrinsically rewarding, and is associated with greater enjoyment and greater activity in reward-related brain regions. Whether similar reward mechanisms support word learning in children, and whether they differ as a function of ability, remains unknown. We used functional magnetic resonance imaging (fMRI) to examine neural responses during contextual word learning in 25 children aged 11-13 years with typical reading skills and in 20 age-matched children with dyslexia. Neurotypical readers showed enhanced activation in core reward-processing regions, including the ventral striatum, when successfully learning the meanings of novel words. In contrast, children with dyslexia did not exhibit comparable reward-related responses despite performing the same task. Crucially, this group difference was specific to word learning, as no significant group differences were observed in ventral striatal responses during a non-linguistic monetary reward task. In addition, to confirm the behavioural relevance of these neural findings, we examined an age-matched, independent sample of children. We found that stronger reading skills were associated with greater enjoyment during successful word learning. Together, these results suggest that interactions between reward and language systems during contextual word learning is influenced by reading proficiency. Reduced intrinsic reward responses to successful language learning may contribute to differences in reading development and have implications for the design of more engaging and effective reading interventions for struggling readers. Significance statementWe investigated how school-age childrens brains learn new words from context, highlighting the important role of reward systems in this process. We show that ventral striatum, a core region associated with reward processing, is activated when children learn the meaning of new words. This suggests learning the meaning of a new word can be its own reward, driving further learning and engagement. Yet, children with dyslexia showed reduced brain activity in the ventral striatum during language learning, even when they successfully learned words. These findings underscore the importance of understanding the mechanisms through which learning becomes rewarding, with implications for designing more engaging and effective reading interventions