ObjectiveFew studies have focused on the neuroanatomy of aggressive behavior in children younger than 10 years. Here, we explored the neuroanatomical correlates of aggression in a population-based sample of 6- to 9-year-old children using a multiple-informant approach.MethodsMagnetic resonance (MR) scans were acquired from 566 children from the Generation R study who participated in the Berkeley Puppet Interview and whose parents had completed the Child Behavior Checklist. Linear regression analyses were used to examine associations between aggression and amygdala and hippocampal volume. We performed surface-based analyses to study the association between aggression and cortical thickness, surface area, and gyrification.ResultsAggressive behavior was associated with smaller amygdala (p < .05) but not hippocampal volume. Aggression was associated with a thinner cortex in the left precentral cortex (p < .01) and in a cluster including the right inferior parietal, supramarginal, and postcentral cortex (p < .001). Gender moderated the association between aggression and cortical thickness in the right medial posterior cortex (p = .001) and the right prefrontal cortex (p < .001). Aggression was associated with decreased gyrification in a large cluster including the right precentral, postcentral, frontal, and parietal cortex (p = .01). Moreover, aggression was associated with decreased gyrification in the right occipital and parietal cortex (p = .02).ConclusionWe found novel evidence that childhood aggressive behavior is related to decreased amygdala volume, decreased sensorimotor cortical thickness, and decreased global right hemisphere gyrification. Aggression is related to cortical thickness in regions associated with the default mode network, with negative associations in boys and positive associations in girls.Electronic supplementary materialThe online version of this article (doi:10.3758/s13415-015-0344-9) contains supplementary material, which is available to authorized users.

Prosocial behavior plays an important role in establishing and maintaining relationships with others and thus may have important developmental implications. This study examines the association between cortical thickness and prosocial behavior in a population-based sample of 6- to 9-year-old children. The present study was embedded within the Generation R Study. Magnetic resonance scans were acquired from 464 children whose parents had completed the prosocial scale of the Strengths and Difficulties Questionnaire. To study the association between cortical thickness and prosocial behavior, we performed whole-brain surface-based analyses. Prosocial behavior was related to a thicker cortex in a cluster that covers part of the left superior frontal and rostral middle frontal cortex (p < .001). Gender moderated the association between prosocial behavior and cortical thickness in a cluster including the right rostral middle frontal and superior frontal cortex (p < .001) as well as in a cluster covering the right superior parietal cortex, cuneus, and precuneus (p < .001). Our results suggest that prosocial behavior is associated with cortical thickness in regions related to theory of mind (superior frontal cortex, rostral middle frontal cortex cuneus, and precuneus) and inhibitory control (superior frontal and rostral middle frontal cortex).

High and stable levels of aggression and the presence of aggressive behaviour in multiple settings according to different informants are risk factors for later problems. However, these two factors have not been investigated in early childhood. The present study investigates trajectories of parent-reported child aggression from 1.5 up to 6 years of age and their association with aggressive behaviour, attention problems and rule-breaking behaviour in a different setting, as reported by the teacher. In a longitudinal population-based cohort study, parent-reported measures of aggressive behaviour were obtained using the CBCL when children were 1.5, 3, and 6 years of age (n ¼ 4,781). Teacher-reported problem behaviour at school was assessed at age 6.5, using the TRF questionnaire (n ¼ 2,756). Growth mixture modelling yielded three aggression trajectories, with high increasing (3.0%), intermediate (21.3%), and low decreasing (75.7%) aggression levels. Children in trajectories with higher and increasing levels of aggression showed more teacher-reported aggressive behaviour, attention problems and rule breaking behaviour. However, parent-reported aggression at age six predicted problem behaviour at school to the same extent as did the aggression trajectories, suggesting that the incremental value of trajectories is not always self-evident.