Electrocortical dynamics reflect age-related differences in movement kinematics among children and adults.

Previous neuroimaging and behavioral studies demonstrated structural and functional changes in the motor system across childhood. However, it is unclear what functionally relevant electrocortical processes underlie developmental differences in motor planning and control during multijoint, goal-directed movements. The current study characterized age-related differences in electrocortical processes during the performance of discrete aiming movements in children and adults. Electroencephalography and movement kinematics were recorded from 3 groups of participants (n = 15 each): young children (mean 6.7 years), older children (mean 10.2 years), and adults (mean 22.1 years). Age-related differences were evident in the electroencephalographic (EEG) signals. First, young children exhibited less movement-related activity in task-relevant motor areas compared with adults (movement-related cortical potentials). Second, young children exhibited greater activation (less alpha power) of the frontal areas and less activation of the parietal areas as compared with the other groups. At the behavioral level, young children made slower and jerkier movements, with less consistent directional planning compared with older children and adults. Significant correlations were also found between EEG and movement kinematic measures. Taken together, the results of this study provide evidence that age-related differences in the quality of motor planning and performance are reflected in the differences in electrocortical dynamics among children and adults.