Value-based decision-making is crucial for human behavior and learning, pervades our daily life and goes astray in psychiatric disorders such as schizophrenia and depression. The neural activity of brain regions producing and being influenced by the neurotransmitter dopamine has been associated with value-based decision-making processes. By extension, one would expect dopamine systems, mainly midbrain regions and their striatal projections, to play a role in value-based decisions, such as whether a specific reward is worth enduring some punishment. It is a matter of debate, but of surprisingly little empirical investigation, whether the rewarding and punishing aspects of value differentially or similarly depend on the dopamine system. The project DOPANF aimed to clarify this issue by investigating dynamic changes of dopamine-related neural activity. DOPANF developed two new paradigms to shed light on this important, but neglected topic for public health and subjective well-being. Specifically, DOPANF used recent neuroscientific and technological developments: real-time imaging for immediate analysis of neural activity in the midbrain and graph-theory connectivity analysis for algorithmic capture of related activity spatially distributed throughout the brain. By observing their own brain activity as neurofeedback in real time, participants learned to volitionally up- and downregulate activity in the dopamine system. The first data analysis revealed new findings about the mechanisms of learning the self-regulation of the dopaminergic midbrain. I investigated the mechanistic control of the dopaminergic midbrain. The findings underpin the theory of reinforcement learning as learning mechanism for the first time in human brain data. Furthermore, the analysis involved the spatially distributed cognitive control network in successful self-regulation of the dopaminergic midbrain. On the behavioral level, we found that learning of volitional self-regulation depends on individual sensitivity to reward. These findings might help tailor future experiments and treatments to specific participants and patients.
The second experiment on adaptive neurofeedback control of the dopaminergic midbrain is currently still exploited and will give novel insights into the process of making decisions to exert mental effort dependent on dopaminergic activity. With this, DOPANF aims to achieve a more precise understanding of decision-making and elucidate the exact role of the dopaminergic midbrain in value processing and its impact on effort discounting. Overall, these findings provide a knowledge basis for a better understanding of psychiatric disorders involving the dopaminergic midbrain, such as depression, schizophrenia and addiction.
