Figure 1.

Whole-brain distribution of surviving neuromagnetic low-beta ERD (cool colors) and ERS (warm colors) during covert verb generation, and their corresponding laterality indices. The maps show top 5% of ERD or ERS for each age tercile. Within each contrast, the colour scaling is set from 95th to 100th percentiles. Across ages and contrasts, magnitude of t-values corresponding to percentiles are not consistent. Maps in (A) shows that children (above) elicit bilateral, diffuse and distributed low-beta ERD (above), which becomes less bilateral and more focalized for older children (middle) and is lateralized to the left perisylvian region in adolescents (below). The scatterplot of ERD LI (right) shows that ERD becomes increasingly left lateralized with age; the trajectory is linear across development. Maps in (B) show that ERS in children (above) is also bilateral but less so in older children (middle) and in adolescents (below) is lateralized to the right hemisphere. The scatterplot of ERS LI (right) shows that ERS becomes increasingly right lateralized with age; the trajectory is nonlinear (quadratic fit).