The pace of vocabulary growth during preschool predicts cortical structure at school age

• Published in: Neuropsychologia 2017-04, Vol.98, p.13-23
• Main Authors: Asaridou, Salomi S., Demir-Lira, Özlem Ece, Goldin-Meadow, Susan, Small, Steven L.
• Format: Article
• Language: English
• Subjects: Age Factors; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Child; Child, Preschool; Cortical thickness; Diffusion Magnetic Resonance Imaging; Female; First language acquisition; Gray Matter - diagnostic imaging; Humans; Imaging, Three-Dimensional; Infant; Language Development; Longitudinal; Male; Models, Psychological; Neural Pathways - diagnostic imaging; Predictive Value of Tests; Probabilistic tractography; Social Class; Vocabulary; Vocabulary growth; White Matter - diagnostic imaging; White matter connectivity
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2016.05.018

Children vary greatly in their vocabulary development during preschool years. Importantly, the pace of this early vocabulary growth predicts vocabulary size at school entrance. Despite its importance for later academic success, not much is known about the relation between individual differences in early vocabulary development and later brain structure and function. Here we examined the association between vocabulary growth in children, as estimated from longitudinal measurements from 14 to 58 months, and individual differences in brain structure measured in 3rd and 4th grade (8–10 years old). Our results show that the pace of vocabulary growth uniquely predicts cortical thickness in the left supramarginal gyrus. Probabilistic tractography revealed that this region is directly connected to the inferior frontal gyrus (pars opercularis) and the ventral premotor cortex, via what is most probably the superior longitudinal fasciculus III. Our findings demonstrate, for the first time, the relation between the pace of vocabulary learning in children and a specific change in the structure of the cerebral cortex, specifically, cortical thickness in the left supramarginal gyrus. They also highlight the fact that differences in the pace of vocabulary growth are associated with the dorsal language stream, which is thought to support speech perception and articulation. •Children differ greatly in the pace at which they acquire their vocabulary.•Pace of vocabulary growth longitudinally estimated in children 14–58 months old.•Vocabulary growth predicted cortical thickness in the left supramarginal gyrus.•Supramarginal gyrus connected to the frontal lobe via a dorsal fiber tract.