Erhard, Peter
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Item-typ:Veröffentlichung, Neural correlates of acute-induced stress and decision-making under risk: an fMRI study(2025-10-29); ; Many situations in daily life require making risky decisions under stressful conditions. In the current behavioral literature, the effects of stress on risky decision-making are inconsistent, and there is limited research investigating post-stress risky decisions from a neural perspective. Identifying neural correlates of post-stress risky decision-making might help to improve the targeted behavioral interventions for risk adjustment. Furthermore, the investigation of post-stress risky decisions from a neuroscientific perspective might shed light on underlying neural/cognitive mechanisms that can moderate the impact of stress on decision-making and offer insights unattainable through behavioral methods alone. Thus, in this dissertation, functional Magnetic Resonance Imaging (fMRI) was employed to assess the neural correlates of stress as well as post-stress risky decision-making. The study consisted of four experimental blocks: stress, post-stress decision-making, control, and post control decision-making. The design was within-subject and all participants were subjected to stress and control conditions in a counterbalanced order. Both stress and control conditions were followed by a “decision-making under risk” task directly after the stress exposure in a single fMRI session with a concurrent Electrodermal Activity (EDA) measurement to confirm the stress manipulation. Stress was induced by asking participants to solve mental arithmetic tasks under time pressure & social-evaluative threat while receiving negative feedback. During the decision-making task, participants chose between a safe and a risky option (binary lottery task) with monetary incentives and known probabilities of winning. Self-reported stress levels and EDA data confirmed that the stress induction was successfully implemented. Participants took less risky decisions post-stress than post-control. An fMRI contrast analysis revealed that the right fronto-opercular and the left anterior part of the dorsolateral prefrontal cortex (dlPFC; an area critical for executive functioning and cognitive control) exhibited significantly lower activation during decisions post-stress than decisions post-control. The results indicate that decisions taken immediately after exposure to the acute stressor are associated with reduced activation in the regions of the dlPFC, possibly leading to less deliberate and less risky decision-making post-stress. Interventions to increase dlPFC activation might be suitable to improve the quality of decision-making post-stress, alleviating the effects of stress.Dissertation27 35 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Neural Correlates of risk-taking with social and financial incentives – an fMRI study(2022-11-30); ; ; This thesis investigates the neural basis of risk-taking in humans across different incentive domains. While changes in incentives are known to alter behavior, current neuropsychological research on risk-taking focuses almost exclusively on financial and token incentives. Whether and to what degree neural correlates depend on the incentive remains an open question, hindering transferability of findings from the laboratory context to the real world. This thesis is a first step in generalizing findings on the neural correlates of risk-taking to other incentive domains. First, as a basis for further analyses, a meta-analysis of functional magnetic resonance imaging (fMRI) studies on human risk-taking was conducted. A general risk-taking brain-network was identified, and several experimental design parameters were found to have an influence on its extent. These findings help inform future experimental design decisions and serve to explain differences in findings of prior studies. Second, brain activation during risk-taking with social and financial incentives was measured with fMRI in 40 participants. Findings on neural correlates were broadly similar across incentives, with their conjunction largely matching the network identified through the meta-analysis. However, the right inferior parietal lobule (IPL) was more strongly involved if incentives were financial compared to social. Exploratory correlational analyses tie this finding to participants behavior in the social condition. The findings place the IPL as a possible source of intra- and inter-individual differences in risk-taking propensity between domains. Future research making use of recent developments in bayesian multilevel modeling and precision fMRI could help understand its exact role.Dissertation532 274