Adolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking,... Show moreAdolescence, defined as the transition phase between childhood and adulthood, is a time of many physical, cognitive and social-emotional changes. It is a natural time of exploring, thrill seeking, and for eventually setting long-term goals and aspirations. One of the most prominent findings is that adolescents take more risks than children or adults. The focus of this thesis is on adolescent risk taking behavior. The goal is to identify individual difference factors that are related to risk taking behavior and assess how these variables change over development. Adolescence is associated with major changes in hormonal levels, brain function and social environment. In this thesis it is tested how changes in pubertal development, brain function and social environment together influence real life risk taking. The studies in this thesis show that neural responses to rewards in the striatum are elevated during adolescence. This response is influenced by chronological age, pubertal development, personality and the social context. Importantly, the striatum response to rewards is related to real life risk taking behavior and therefore has functional relevance. The results of this thesis provide vital insight in the complex relationship between reward processing and real life risk taking behavior. Show less
This thesis aimed to investigate the neurobiological mechanisms of adolescent onset depression and anxiety disorders. A longitudinal fMRI study design was used that included both task related brain... Show moreThis thesis aimed to investigate the neurobiological mechanisms of adolescent onset depression and anxiety disorders. A longitudinal fMRI study design was used that included both task related brain activation and resting state functional connectivity. All participants were scanned three times in a six-month period. In between scan sessions the adolescents from the clinical group received treatment as usual. Adolescents from the control group were scanned within the same time interval but did not receive treatment. During a scan session several MRI parameters were collected including task based fMRI (emotional face processing task) and resting state fMRI. We also administered several questionnaires about derpession and anxiety symptomatology. It was demonstrated that adolescents with depressive and anxiety disorders show differentiating patterns of amygdala reactivity and connectivity compared to a healthy control group. Furthermore, using a dimensional approach and taking individual differences in self-reported depression and anxiety symptoms into account highlighted the role of self-reported anxiety symptoms in amygdala reactivity during emotional faces processing. These findings indicate that the amygdala indeed is an important region involved in emotional face processing and that focusing on this region can provide further insights in the development and persistence of depressive and anxiety disorders in adolescents. Show less
