Trajectories of brain development from childhood to adulthood: Influencing factors and behavioral outcomes

The human brain continues to develop after birth and across childhood and adolescence. Genes, maturation and experiences dynamically interact in shaping who we are, our cognitive functions and our brain at any given time. Over the last decade, the use of neuroimaging techniques, particularly magnetic resonance imaging (MRI), have yielded new knowledge on how the brain changes during development and throughout life. However, in order to map these changes more precisely and better understand which factors influence this development, as well as its consequences, studies that follow the same individuals over time, longitudinal studies, are critical. In this research project, we have followed a group of children and adolescents over three time-points. We have collected data using neuroimaging (MRI and EEG), cognitive tests, questionnaires and biological samples. The results from the project have contributed to a more detailed mapping of the structural and functional development of the brain from childhood to adulthood. Further, the project has resulted in new knowledge on how brain development is related to different aspects of psychological development, including personality traits, prosocial behavior, mental health, and cognitive functions. The project has also collaborated with other projects studying typical neurocognitive development, as well as projects studying neurocognitive development in groups with different risk factors.

The project has yielded new knowledge about brain development and influencing genetic and early environmental factors and behavioral outcomes, and made an important foundation for comparison with samples of psychiatric disorders, neurological disease and the outcome of persons with different biomedical risk factors. We have also published several methods and best practice papers, aiming to advance the research field.

The human brain undergoes enormous development from birth to adult age. Insight into this multifaceted process has been tremendously enhanced over the last two decades by neuroimaging studies, documenting sustained changes in the cerebral cortex, subcorti cal structures and white matter. Longitudinal studies with multiple time-points are however needed to track the trajectories of structural and functional changes in the brain's neuronal tissue and connections and how these vary across different brain regi ons and between individuals. Genes and environmental factors interact in forming our brains and mental capacities and there is increasing recognition of the importance of developmental processes for later cognitive functions and behavioral patterns. Longi tudinal studies that allow for direct examination of these relationships in development are however lacking. The focus of the current research project will be to conduct the third longitudinal follow-up in the project and analyze behavioral, magnetic res onance imaging (MRI), functional MRI (fMRI), electroencephalography (EEG), genetic and health registry data from ~300 healthy children and adolescents 8-25 years old. We will also combine these data with similar longitudinal data from ~350 younger childre n and ~215 adult participants. The objectives of the project are to characterize the trajectories of brain development in healthy children and adolescents, explore specific genetic and early environmental influences, and to investigate behavioral outcomes in terms of cognitive functions, scholastic achievements and behavioral adjustment. A comprehensive understanding of how the brain and our cognitive functions change during development is important for understanding characteristic features of childhood a nd adolescence, and is also critical for understanding mature cognition and how development may go awry in neurological and psychiatric disorders and in groups with specific risk factors.