Brain :: Risk taking in human brain – effect of free choice

Risk is a ubiquitous component of the natural world and human life. Although some amount of risk-taking behaviour is desirable and essential for human survival and advancement, excessive risk-taking may underlie pathological conditions such as drug-abuse and compulsive gambling.

Researchers from diverse disciplines are converging to understand how people make decisions under risk. However, not all risks are predicated on the decisions people make, and people are often forced to accept some unavoidable risks.

Whether and how the free choice affects the way the brain handles risk, and why people differ in risk-seeking and risk-aversion, remain unknown.

fMRI was used to measure brain activation patterns when participants earned points by inflating a virtual balloon. Their earnings increased with balloon size, but points were lost if the balloon exploded. Subjects could choose when to stop inflating in the active risk task, while the computer decided for them in the passive risk task. Only voluntary selected risk but not passively experienced risk activated the striatum, insula and ACC, areas related to reward and aversive emotion processing. Decision-making was associated with neural activity in the affectively-neutral right dorsal lateral prefrontal cortex. Moreover, individual variability in risk preference, as determined by their average balloon inflation size, was closely correlated with activity in the midbrain, striatum and insula, suggesting that the sensitivity of the brain?s emotion system to risk determines the amount of risk people will choose. These results contribute to a better understanding of the brain mechanisms underlying risky behavior.

Authors: Hengyi Rao, Marc Korczykowski, John Pluta, John A. Detre

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