Investigating the spatiotemporal neural dynamics of lexico‐semantic activity in 12–18 month old infants by combining magnetoencephalography and magnetic resonance imaging.

Abstract

Knowledge of the neural basis of early language is limited because of the difficulties in assessing functional brain activity during infancy. Consequently, it is unclear whether infants and adults depend on similar underlying neural structures to understand words. Advances in magnetoencephalography combined with magnetic resonance imaging now make it possible to study this population. This method, dynamic statistical parametric mapping (dSPM), has been extensively validated during language processing in adults. Here, dSPM was used to examine the neural correlates of word understanding in 12–18 month old infants. Specifically, it was discovered that the lexico‐semantic neural processes indexed as the adult N400 event‐related component are functional during early stages of word learning and depend on similar left frontotemporal brain areas. These findings demonstrate that dSPM can be used to localize functional brain activity associated with language processes in pediatric populations. Moreover, discovery of a fundamental lexico‐semantic process present throughout the rapid burst of language acquisition permits this process to be quantified and thus related to behavioral and neural development and their disorders. Together, these findings illustrate the potential for dSPM and other non‐invasive neuroimaging techniques to increase current understandings of the neural basis of early language development. [Work supported by the Kavli Institute for Brain and Mind and NIH/NINDA R01 NS018741.]