Mapping the developmental course of the multispectral dynamics serving executive functioning

While the cortical regions serving basic sensory processing undergo extensive maturation during early childhood that slows considerably during adolescence, the circuitry and neural dynamics serving higher-order executive functions continue to develop throughout adolescence and early adulthood. While many studies have mapped the accompanying changes in cortical thickness and brain activation, far fewer have quantified changes in the cortical dynamics that likely underlie the improvements seen in executive function during this developmental window. In the current study, we use an advanced dynamic functional mapping technique based on high-density magnetoencephalography (MEG) to quantify neural oscillatory responses during a validated executive function task in 80 typically developing 11-16 year-olds. All MEG data were transformed into the time-frequency domain and significant oscillatory responses were imaged using a beamforming approach. The resulting voxel-wise, whole-brain functional images were examined for developmental changes using chronological age, sex, and sex-by-age interactions. Our primary results indicated that alpha oscillations in the right dorsolateral prefrontal cortex and anterior cingulate cortex became significantly weaker (i.e., less negative relative to baseline) with increasing age. Likewise, the strength of gamma oscillations also declined with increasing age in the left prefrontal cortex, left superior parietal cortices, and the right supplementary motor area. Critically, significant age-by-sex interactions in the alpha and gamma range were identified in the bilateral parietal cortices. These findings reveal developmental changes in alpha and gamma oscillatory dynamics in key cortical regions for higher-order cognitive function which may support the refinement of executive function during adolescence and early adulthood.