Neurophysiological mechanisms of emotion regulation for subtypes of externalizing children

Children referred for externalizing behavior problems may not represent a homogeneous population. The objective of this study was to assess the neural mechanisms of emotion regulation that might distinguish subtypes of externalizing children from each other and from their typically developing age-mates. Children with pure externalizing (EXT) problems were compared with children comorbid for externalizing and internalizing (MIXED) problems and with age-matched controls. Only boys were included in the analysis because so few girls were referred for treatment. A go/no-go task with a negative emotion induction was used to examine dense-array EEG data together with behavioral measures of performance. Four event-related potential (ERP) components tapping inhibitory control or self-monitoring were assessed including the inhibitory N2, the error-related negativity (ERN), the error positivity (Pe) and the frontal inhibitory P3 (iP3). Source models were constructed estimating the cortical generators of these components. The MIXED children's N2s increased in response to the emotion induction, resulting in greater amplitudes than EXT children in the following trial block. MIXED and EXT children showed increased N2 latencies compared to controls. ERN amplitudes were greatest for control children and smallest for EXT children with MIXED children in between, but only prior to the emotion induction. N2 component latencies were shorter for controls but only before and after the induction block with a significantly faster N2 for controls only in block C relative to MIXED children. Latencies for the ERN component were longer for the EXT children in blocks A and B relative to both MIXED and controls. Mixed results were found for both the Pe and frontal P3 amplitude. Pe amplitudes were smallest for control children in blocks A and B relative to both clinical groups. Pe latencies were consistent across groups with the exception of block B where EXT children showed an increase in component latency. Frontal P3 amplitudes were larger for EXT children in blocks A and B while P3 latencies were longer for both clinical groups across all blocks. These ERP results were paralleled by behavioral differences in response time and performance monitoring. ERP activity was localized to cortical sources suggestive of the dorsal anterior cingulate for control children, posterior cingulate areas for the EXT children, and both posterior cingulate and ventral cingulate/prefrontal regions for the MIXED children. These findings highlight different mechanisms of self-regulation underlying externalizing subtypes and point toward distinct developmental pathways and treatment strategies.