Neural Changes Associated with Treatment Outcome in Children with Externalizing Problems

The current thesis directly investigated whether changes in the neural correlates of self-regulation (SR) are associated with the effectiveness of treatment for children’s externalizing problems. In order to test this, seventy-one children 8–12 years of age with clinical levels of externalizing behaviour and their parents completed a 12-week cognitive behavioural therapy program (12 sessions) with a parent management training component that was aimed at improving SR. Electroencephalogram (EEG) correlates of SR were evaluated before and after treatment with a go/no-go task requiring inhibitory control on the children. Results showed that event-related potential (ERP) correlates of SR, such as the frontal N2 and frontal P3 event-related potential magnitudes, differed between the clinical sample and a matched comparison group before treatment: the clinical sample had larger N2 magnitudes and smaller frontal P3 magnitudes. Children who showed improvement (45%) with treatment demonstrated a decrease in the magnitude of the N2 in comparison with children who did not improve. For improvers only, source analysis during the time period of the N2 modeled activation decreases in dorsomedial and ventromedial prefrontal cortex as well as the anterior medial temporal lobe. A decrease in N2 magnitudes and corresponding reductions in source activation, in children who improved with treatment, might reflect improved efficiency in the neural mechanisms of SR. These findings may be important steps toward a better identification of neural markers of SR and a better understanding of the mechanisms of treatment efficacy.Ph