Brain network disruption underlying externalizing behaviors

Externalizing behaviors such as aggression, defiance, and hyperactivity are common in autistic and non-autistic children. Research suggests that externalizing behaviors are not associated with intellectual functioning (FSIQ), gender, language, or autism symptom severity. Instead, recent studies suggest externalizing behaviors are more related to and are often linked to difficulties in executive functioning (EF). The current study examined behavioral and neural predictors of externalizing behaviors in a transdiagnostic sample of school-age children (N = 90; ages 7-13 years; 48 autistic, 42 non-autistic). Parents completed measures of EF (Behavior Rating Inventory of Executive Function, Second Edition; BRIEF-2) and externalizing behaviors (Behavior Assessment System for Children, Third Edition; BASC-3). Children completed resting-state fMRI scans. After controlling for age and FSIQ, the BRIEF-2 composite index scores (Behavioral, Emotional, and Cognitive Regulation) significantly predicted externalizing behaviors. Seed-to-seed analyses revealed positive associations between externalizing behaviors and connectivity among the left superior parietal lobule, left inferior parietal lobule, anterior insula, and lateral frontal ECN nodes. Seed-to-voxel analyses showed widespread alterations, including increased connectivity within frontoparietal executive regions alongside reduced connectivity in salience-related areas, such as cingulate and insula. This dual connectivity profile suggests a neural mechanism involving compensatory executive engagement paired with diminished salience processing that may contribute to behavioral dysregulation. These results suggest that executive dysfunction, at both the behavioral and neural levels, is associated with externalizing behaviors in children regardless of diagnostic status. Findings underscore the potential utility of EF-based interventions for mitigating externalizing problems in both autistic and non-autistic populations.