Neural Correlates of risk-taking with social and financial incentives – an fMRI study

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.