BMI Seminar // Christian Ruff: Stress changes risk-taking by altering Bayesian magnitude coding in parietal cortex

Acute stress is an inevitable aspect of life, with long-lasting consequences for physical and financial well-being. Previous research documents a link between acute stress and altered risk preference, with suggestions that these behavioral effects of stress may contribute to the perpetuation of poverty. However, despite ample research, little is known about the neurocognitive processes that translate stress into altered risky decision-making. In my talk, I will present a recent research line in my lab that sheds light on these processes. Based on our recent findings that risk-taking can originate from noisy and biased perceptual processing of payoffs (Garcia et al., 2023, Nature Human Behavior), we investigated how laboratory-induced stress changes distinct aspects of these processes -  specifically, either noise in sensory representation or prior beliefs. Importantly, we find with fMRI and population coding models that changes in these cognitive variables relate directly to how numerosities are represented in the parietal magnitude processing system. Our results therefore suggest a mechanistic pathway by which stress effects on neural function can lead to changes in risk-taking.