Characterizing the normal developmental trajectory of expressive language lateralization using magnetoencephalography.

To characterize the developmental trajectory for expressive language representation and to test competing explanations for the relative neuroplasticity of language in childhood, we studied 28 healthy children and adolescents (aged 5-19 years) participating in a covert verb generation task in magnetoencephalography. Lateralization of neuromagnetic responses in the frontal lobe was quantified using a bootstrap statistical thresholding procedure for differential beamformer analyses. We observed a significant positive correlation between left hemisphere lateralization and age. Findings suggest that adult-typical left hemisphere lateralization emerges from an early bilateral language network, which may explain the pediatric advantage for interhemispheric plasticity of language.