Abstract

The functions of rewards are based on their effects on behaviour and are less directly governed by the physics and chemistry of sensory inputs. Therefore the investigation of neural mechanisms underlying reward functions is helped by behavioural theories, including animal learning theory and economic utility theory. The reward system of the brain is comprised of specific structures, including the midbrain dopamine neurons, orbitofrontal cortex, striatum and amygdala. The presentation will describe neural signals in these structures related to basic decision variables, such as the magnitude, probability, expected value and variance (risk) of reward. Temporal discounting shows that reward value is coded subjectively. Some risk signals depend on individual risk attitudes, and risk influences neuronal value signals.