Developing an intricate social brain: functional and structural correlates of socioemotional skills and their association with mental well-being

Socioemotional skills encompass a large set of abilities, which develop from early on and continue to being fine-tuned until late adulthood. The mastery of socioemotional abilities is associated with better social bonds and general psychological well-being in everyday life. Furthermore, it may also play an important role during challenging life circumstances. The fundamentals of mentalizing, the ability of perspective-taking, are acquired in early childhood laying the foundation for the development of more complex social skills across life. The ability to infer mental states aids interpersonal relations and is commonly considered beneficial. However, overly high, or low levels of mentalizing might lead to disturbances in social interactions or elevated stress. The neurobiological foundation for mentalizing has been well studied in adults, however evidence in developmental groups is still lagging behind, despite considerable advances in pediatric neuroimaging over recent years. The main aim of this thesis was to summarize existing knowledge and generate new evidence on the development of the neural correlates for mentalizing. Furthermore, links between the neural correlates of socioemotional processing (i.e., mentalizing or emotion regulation) and psychosocial functioning are investigated. To achieve these goals, we first conducted a meta-analysis synthesizing theory of mind-related neural findings in children and adolescents comparing them to adult findings. Furthermore, we developed and validated a novel cartoon story-based theory of mind functional magnetic resonance imaging task feasible for young children. Finally, the onset of Covid-19 was recognized as a possibly impactful adverse global experience, allowing for the investigation of socioemotional and psychological well-being during challenging life circumstances. Neural correlates of mentalizing and emotion regulation skills were investigated in relation to mental health outcomes during the Covid-19 pandemic. Within this thesis I first present meta-analytic evidence for an early development of the mentalizing network. Large correspondence of child, adolescent, and adult neural findings exist (as reflected by activation in temporoparietal junction, precuneus and middle medial prefrontal cortex across all age groups) but continuous change is observed across age, including more extensive activation pattern with increased age. Secondly, we developed a novel cognitive and affective theory of mind cartoon task (CAToon), which was evaluated behaviorally as well as through fMRI in children and adults. Our findings warrant future use of the task in developmental neuroimaging studies of mentalizing. Third, during stressful life circumstances, here associated with the Covid-19 pandemic, variations in adults’ and children’s mental health are observed. And finally, brain structure (i.e., emotion regulatory areas) and function (i.e., neural activation elicited during mentalizing) measured prior to the pandemic was linked to variables of psychosocial functioning in children and adults (e.g., fears about contamination or caregiving burden, anxiety, or depression). In summary, my thesis I provides novel neuroimaging evidence that describes the development of socioemotional skills across childhood and adulthood and present selected examples of the association of socioemotional processes with mental well-being. In the future, neurodevelopmental studies assessing socioemotional skills and psychosocial functioning could profit from longitudinal approaches and the inclusion of a combination of neurophysiological and behavioral measures from an early age