Neural correlates of cognitive control in childhood and adolescence: disentangling the contributions of age and executive function.

Dense-array (128-channel) electroencephalography (EEG) was used to record event-related potentials (ERPs) from 33 participants between 7 and 16 years of age while they performed a Go/Nogo task. The frontal (Nogo) N2 component of the ERP was taken as an index of cognitive control, and examined in relation to both age and independent assessments of executive function (EF), including the Iowa Gambling Task (IGT), the Stroop task, a delay discounting task, and backward digit span. Better performance on the IGT and the Stroop task was associated with smaller N2 amplitudes, over and above effects of age. N2 latencies decreased with age but were not predicted by EF. Source modeling of the N2 revealed neural generators in areas suggestive of cingulate cortex and orbitofrontal cortex, and the locations of these generators varied systematically with EF (IGT and Stroop task): the cingulate generator was more anterior for good EF participants at all ages; the orbitofrontal generator was relatively left lateralized for younger and for poorer EF participants. Taken together, these findings suggest that age-related decreases in N2 amplitude, but not N2 latency, reflect the development of cognitive control and cannot be attributed solely to incidental changes that may affect assessments of the N2 (e.g., increases in skull thickness). Functionally relevant decreases in N2 amplitude may reflect changes in the regions of cortex giving rise to the N2.