This dissertation explores the structure and function of the human dopaminergic midbrain, focusing on the ventral tegmental area (VTA) using advanced neuroimaging techniques, including high-field... Show moreThis dissertation explores the structure and function of the human dopaminergic midbrain, focusing on the ventral tegmental area (VTA) using advanced neuroimaging techniques, including high-field 7T MRI. Historically less studied than the substantia nigra (SN), the VTA is essential for cognitive functions like reward-based learning and motivation. However, its deep location and complex structure make it challenging to study with conventional methods. The dissertation introduces a new probabilistic atlas of the VTA based on high-resolution MRI scans, improving anatomical precision. It examines the structural and functional connectivity of the VTA and SN, revealing differences in white matter tract density. The work also investigates working memory and reward prediction error (RPE) processing, highlighting the VTA's involvement in working memory updating and challenging existing models of subcortical cognitive functions. Overall, the study enhances our understanding of the VTA and SN and provides new tools for more precise neuroimaging research. Show less
The ventral tegmental area dopamine (VTA-DA) mesolimbic circuit processes emotional, motivational, and social reward associations together with their more demanding cognitive aspects that involve... Show moreThe ventral tegmental area dopamine (VTA-DA) mesolimbic circuit processes emotional, motivational, and social reward associations together with their more demanding cognitive aspects that involve the mesocortical circuitry. Coping with stress increases VTA-DA excitability, but when the stressor becomes chronic the VTA-DA circuit is less active, which may lead to degeneration and local microglial activation. This switch between activation and inhibition of VTA-DA neurons is modulated by e.g. corticotropin-releasing hormone (CRH), opioids, brain-derived neurotrophic factor (BDNF), and the adrenal glucocorticoids. These actions are coordinated with energy-demanding stress-coping styles to promote behavioral adaptation. The VTA circuits show sexual dimorphism that is programmed by sex hormones during perinatal life in a manner that can be affected by glucocorticoid exposure. We conclude that insight in the role of stress in VTA-DA plasticity and connectivity, during reward processing and stress-coping, will be helpful to better understand the mechanism of resilience to breakdown of adaptation. Show less
Opstal, A.M. van; Kaal, I.; Berg-Huysmans, A.A. van den; Hoeksma, M.; Blonk, C.; Pijl, H.; ... ; Grond, J. van der 2019
