Risk prediction error coding in orbitofrontal neurons.

Risk is a ubiquitous feature of life. It plays an important role in economic decisions by affecting subjective reward value. Informed decisions require accurate risk information for each choice option. However, risk is often not constant but changes dynamically in the environment. Therefore, risk information should be updated to the current risk level. Potential mechanisms involve error-driven updating, whereby differences between current and predicted risk levels (risk prediction errors) are used to obtain currently accurate risk predictions. As a major reward structure, the orbitofrontal cortex is involved in coding key reward parameters such as reward value and risk. In this study, monkeys viewed different visual stimuli indicating specific levels of risk that deviated from the overall risk predicted by a common earlier stimulus. A group of orbitofrontal neurons displayed a risk signal that tracked the discrepancy between current and predicted risk. Such neuronal signals may be involved in the updating of risk information.