The embryonic development of the human cochlea (the organ of hearing) has been investigated for over one hundred years. However, little is still known about the development on a cellular and... Show moreThe embryonic development of the human cochlea (the organ of hearing) has been investigated for over one hundred years. However, little is still known about the development on a cellular and protein level, which is important to better understand etiologies and pathologies of various types of sensorineural hearing loss. Knowledge of the normal gene expression patterns and cell fate specification in the human cochlea has therefore the potential to aid in the development of gene and cell-based therapeutic strategies. For this reason, we acquired a series of human fetal cochlea of different stages of gestation and investigated several aspects of the normal development of the human cochlea such as the hair cells, the spiral ganglion neurons and the stria vascularis. Also, we investigated the neural crest stem cells residing in the hair follicle bulge. We showed that a protein (TUBB3) often used in immunochemistry to detect a neuron is also expressed both in skin and hair follicle melanocytes in humans meaning that the proposed neural crest stem cell residing in the hair follicle bulge might need revision. Show less
Children and adolescents who are chronically rejected by their peers suffer from widespread impairments in daily life, ranging from poor academic achievement and dropping out of school, to... Show moreChildren and adolescents who are chronically rejected by their peers suffer from widespread impairments in daily life, ranging from poor academic achievement and dropping out of school, to delinquency and the development of mental health problems. To gain a better understanding of the developmental processes that give rise to such impairments, the research described in this dissertation examined the neurocognitive underpinnings of processes that play a role in the emergence and maintenance of peer group rejection and acceptance. The first part of this dissertation focuses on neurocognitive processes underlying reactions to social exclusion. The second part concentrates on the neurocognitive processes involved in sharing valuable resources, based on the widely established finding that frequent displays of prosocial behaviors, such as cooperating, helping, and sharing, are associated with both gaining and maintaining acceptance among peers. The empirical work in this dissertation demonstrates that a developmental cognitive neuroscience approach provides unique insights into the emotional, regulatory, and socio-cognitive processes thought to play a role in the emergence and maintenance of peer group acceptance and rejection. Show less
Self-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs... Show moreSelf-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs from externally driven inhibition in that it is driven by an internal thought process rather than an external stimulus that tells one to stop. The goal of this thesis was to examine the development of intentional inhibition and compare this with externally driven inhibition. In order to investigate the covert process of intentional inhibition, the research described in this thesis made use of neurobiological measures such as phasic heart rate changes and functional magnetic resonance imaging (fMRI). In addition, to learn more about self-control in context, the final empirical chapter examined intentional and externally driven inhibition in the context of relevant and irrelevant emotions. Show less
