The social relationships we form with other individuals are a fundamental part of human development. In order to establish these relationships it is of key importance for children to develop social... Show moreThe social relationships we form with other individuals are a fundamental part of human development. In order to establish these relationships it is of key importance for children to develop social competence (e.g. the ability to fulfill both others’ and own needs in a social context). The main goal of this thesis was to understand individual differences in social competence in middle childhood, by employing a combination of behavioral, neuroimaging and behavioral genetic approaches. Findings demonstrated that adults and children display social competence by showing helping behavior as a response to observed social exclusion. Additionally, in both adults and children social competence was associated with an integrated set of brain regions involved in socio-cognitive and affective processing, indicating that the neural architecture underlying social competence is already well established in middle childhood. Results on heritability of social competence indicate that individual differences in prosocial tendencies and brain structure might be partly influenced by genetic factors, but that neural and behavioral responses in a specific social context are largely shaped by an individual’s experiences in the (social) environment. This thesis highlights middle childhood as a possible window of opportunity for increasing social competence through training or intervention. Show less
Coppen, E.M.; Grond, J. van der; Hafkemeijer, A.; Wolf, J.J.H.B.; Roos, R.A.C. 2018
Studies of Attention-Deficit/Hyperactivity Disorder (ADHD) have shown developmental changes in the cortical mantle. Different dimensions of cortical morphology, such as surface area and thickness,... Show moreStudies of Attention-Deficit/Hyperactivity Disorder (ADHD) have shown developmental changes in the cortical mantle. Different dimensions of cortical morphology, such as surface area and thickness, relate to different neurodevelopmental mechanisms. As such, studying multiple dimensions may inform us about the developmental origins of ADHD. Furthermore, results from existing longitudinal samples await replication. Therefore, we conducted a longitudinal study of multiple cortical dimensions in a sizable, independent ADHD sample. We analyzed 297 anatomical MRI scans from two matched groups of 94 subjects with ADHD and 94 controls, aged 6–28 years. We estimated the developmental trajectories of cortical volume, surface, thickness and gyrification for 68 regions using mixed-effects regression analysis. Subjects with ADHD had smaller overall cortical volume, predominantly driven by decreases in frontal lobe volume that were associated with reduced surface area and gyrification. Nearly all decreases were stable across development. Only a few decreases survived stringent Bonferroni correction for multiple comparisons, with the smallest detectable Cohen's d |0.43|. There were no between-group differences in cortical thickness, or in subcortical volumes. Our results suggest that ADHD is associated with developmentally persistent reductions in frontal cortical volume, surface area, and gyrification. This may implicate early neurodevelopmental mechanisms regulating cortical expansion and convolution in ADHD. Show less
