Risky Neural Behaviors

Functional magnetic resonance imaging devices have long been a popular way for scientists to see – in real time – which areas of the brain are being activated during research studies. One drawback of the technology, however, is the inability to detect changes on short timescales, making it difficult or even impossible to determine subsecond temporal differences in neural activity. In this study, researchers used magnetoencephalography to determine whether different regions of the brain are active at different times when people make decisions related to risk.

Study participants played an economic stock game with levels of risk in potential investments controlled by the researchers while they monitored neural activity levels in the posterior parietal and dorsomedial prefrontal cortex. The scientists discovered that while these two areas are active at the same time during risk assessment, the former becomes active before the latter.

What’s more, activity levels in each fluctuated independently of one another depending on both the risk probabilities of options and the sizes of their potential rewards. This suggests that separate, specialized brain circuitry work together to deal with different aspects of risk perception, but not at the exact same time.

Rosalyn Moran, PhD

Why It’s Important:
This study supports the theory that risk assessment not only takes place before decision-making, but it also informs it, and that specialized subregions of the brain deal with aspects of risk independently and at different times.

What’s Interesting:
Although it is not known whether the probability of risks in different options directly informs calculations of risks and rewards, it is interesting to note that the likelihood of potential outcomes are a first-order measure of uncertainty. Potential payoffs are a second-order measure, and the brain begins processing the former mere instants before the latter.

Where to Find It:
Symmonds M, Moran R, Wright N, Bossaerts P, Barnes G, Dolan R. The chronometry of risk processing in the human cortex. Front Neurosci, 2013; 7:146.