Peer influence plays a crucial role in the rise of health-risk behaviors during adolescence. However, there is increasing evidence that peer influence can also lead to positive psychosocial... Show morePeer influence plays a crucial role in the rise of health-risk behaviors during adolescence. However, there is increasing evidence that peer influence can also lead to positive psychosocial outcomes, such as prosocial behavior. The main goal of this thesis was to investigate peer influence on risk-taking and prosocial behavior in adolescence and to unravel its underlying neural processes. Findings showed that effects of peers on risk-taking behavior are dependent on the context. Adolescents take into account both social norms from peer feedback and the uncertainty associated with outcomes in risky decisions. Moreover, peers can both increase and decrease prosocial behavior in typically developing (TD) adolescents and those with autism spectrum disorders (ASD), illustrating that peer influence can also lead to more adaptive outcomes. Finally, we studied the neural processes underlying prosocial peer feedback and results indicate that prosocial peer influence is underlined by the social brain network, regions involved in thinking about the self and others. Eventually, the results of this thesis can contribute to interventions aimed at decreasing risk-taking and promoting prosocial behavior in adolescence, with possibly long lasting effects into adulthood. Show less
When trying to understand texts, readers engage in various cognitive processes. If all goes well, the engagement in these cognitive processes during reading results in the construction of a... Show moreWhen trying to understand texts, readers engage in various cognitive processes. If all goes well, the engagement in these cognitive processes during reading results in the construction of a coherent mental representation of the text, the essence of successful reading comprehension. To construct such a representation, readers need to monitor the coherence of the text and of their emerging mental representation of what the text is about. The central aim of the empirical studies described is to examine coherence-monitoring processes across development by measuring reader’s ability to detect coherence breaks during reading of narratives. The first part of this dissertation consists of three empirical studies (chapter 2-4). The first study examined whether good and poor comprehenders at age 8-9 and 10-11 detected coherence-breaks during and/or after reading. The second study builds on the first study by examining the protracted development of coherence monitoring in an adolescent population (ages 10-22) using the same task under more challenging circumstances. The third study explored the neural correlates of coherence-break detection in young adults in an fMRI study. The second part of this dissertation consists of two conceptual chapters in which the results are summarized and discussed in a broader theoretical perspective (chapter 5-6). Show less
Will, G.J.; Crone, E.A.M.; Van Lier, P.A.C.; Güroğlu, B. 2016
The current study examined the effects of oxytocin administration on the response to infant crying in individuals with secure or insecure attachment representations as assessed with the Adult... Show moreThe current study examined the effects of oxytocin administration on the response to infant crying in individuals with secure or insecure attachment representations as assessed with the Adult Attachment Interview. We measured feelings of irritation and the use of excessive force as indicated by grip strength using a handgrip dynamometer during exposure to infant crying in 42 women without children who were administered intranasal oxytocin or a placebo. In addition, amygdala responses to infant crying and control sounds were measured with functional magnetic resonance imaging (fMRI). The effects of oxytocin on reactivity to crying were moderated by attachment security. Oxytocin decreased the use of excessive handgrip force and amygdala reactivity in response to crying in individuals with insecure attachment representations. Our findings indicate that insecure individuals, who show emotional, behavioral, and neural hyperreactivity to crying, benefit the most from intranasal oxytocin. Show less
Klapwijk, E.T.; Lelieveld, G.J.; Aghajani, M.; Boon, A.E.; Wee, N.J.A. van der; Popma, A.; ... ; Colins, O.F. 2016
This thesis focused on the development of creative thinking across adolescence and into adulthood. To this end, a range of creativity tasks, both with and without an fMRI scanner, and before and... Show moreThis thesis focused on the development of creative thinking across adolescence and into adulthood. To this end, a range of creativity tasks, both with and without an fMRI scanner, and before and after training paradigms has been used to ex_amine both age- and experience-related effects on creative thinking performance during functional brain develop_ment. Chapter 1 provides a theoretical background for the research described in chapters 2 to 6. In Chapter 2, developmental trajectories of creative cognition across adolescence and early adulthood were examined using a set of tasks gauging both insight and divergent thinking in the verbal and visual domain. In Chapter 3, behavioral and neural differences for creative problem solving in middle-adolescents and adults were examined. Chapter 4 examined the neural correlates of divergent thinking in adults and adolescents. Chapter 5 focused on the effectiveness of creative ideation training in adolescents and adults. In Chapter 6, the benefits of training creativity in adolescents were examined using fMRI techniques. Finally, Chapter 7 summarizes the main results of the empirical studies presented in this thesis. Here, implications of the results are discussed and suggestions for future research are presented. Show less
Schouten, T.M.; Koini, M.; Vos, F. de; Seiler, S.; Grond, J. van der; Lechner, A.; ... ; Rombouts, S.A.R.B. 2016
Magnetic resonance imaging (MRI) is sensitive to structural and functional changes in the brain caused by Alzheimer's disease (AD), and can therefore be used to help in diagnosing the disease.... Show moreMagnetic resonance imaging (MRI) is sensitive to structural and functional changes in the brain caused by Alzheimer's disease (AD), and can therefore be used to help in diagnosing the disease. Improving classification of AD patients based on MRI scans might help to identify AD earlier in the disease's progress, which may be key in developing treatments for AD. In this study we used an elastic net classifier based on several measures derived from the MRI scans of mild to moderate AD patients (N = 77) from the prospective registry on dementia study and controls (N = 173) from the Austrian Stroke Prevention Family Study. We based our classification on measures from anatomical MRI, diffusion weighted MRI and resting state functional MRI. Our unimodal classification performance ranged from an area under the curve (AUC) of 0.760 (full correlations between functional networks) to 0.909 (grey matter density). When combining measures from multiple modalities in a stepwise manner, the classification performance improved to an AUC of 0.952. This optimal combination consisted of grey matter density, white matter density, fractional anisotropy, mean diffusivity, and sparse partial correlations between functional networks. Classification performance for mild AD as well as moderate AD also improved when using this multimodal combination. We conclude that different MRI modalities provide complementary information for classifying AD. Moreover, combining multiple modalities can substantially improve classification performance over unimodal classification. (C) 2016 The Authors. Published by Elsevier Inc. Show less
Schouten, T.M.; Koini, M.; Vos, F. de; Seiler, S.; Van der Grond, J.; Lechner, A.; ... ; Rombouts, S.A.R.B. 2016
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
Cohn, M.D.; Veltman, D.J.; Pape, L.E.; Lith, K. van; Vermeiren, R.R.J.M.; Brink, W. van den; ... ; Popma, A. 2015
