Mar 2000; V 10 N 3 | Wolfram Schultz, Léon Tremblay1 and Jeffrey R. Hollerman2
This article reviews the neuronal activities related to reward processing in the primate orbitofrontal cortex and basal ganglia, comparing them with the responses of slowly discharging neurons in the striatum and midbrain dopamine neurons. Orbitofrontal neurons showed three main forms of reward-related activity: responses to reward-predicting instructions, activations during the expectation period, and responses following the reward. These activations discriminated between different rewards based on the animals' preferences. Striatal neurons also showed activations related to the expectation and detection of reward, as well as activities related to movement preparation, initiation, and execution. Dopamine neurons responded to both primary rewards and reward-predicting stimuli, and coded an error in the prediction of reward. The study suggests that the investigated cortical and basal ganglia structures exhibit multiple, heterogeneous, and partly simultaneous activations related to specific aspects of rewards, which may represent the neuronal substrates of reward processing during learning and established behavioral performance. The processing of reward expectations indicates access to central representations of rewards, which could be used for the neuronal control of goal-directed behavior.This article reviews the neuronal activities related to reward processing in the primate orbitofrontal cortex and basal ganglia, comparing them with the responses of slowly discharging neurons in the striatum and midbrain dopamine neurons. Orbitofrontal neurons showed three main forms of reward-related activity: responses to reward-predicting instructions, activations during the expectation period, and responses following the reward. These activations discriminated between different rewards based on the animals' preferences. Striatal neurons also showed activations related to the expectation and detection of reward, as well as activities related to movement preparation, initiation, and execution. Dopamine neurons responded to both primary rewards and reward-predicting stimuli, and coded an error in the prediction of reward. The study suggests that the investigated cortical and basal ganglia structures exhibit multiple, heterogeneous, and partly simultaneous activations related to specific aspects of rewards, which may represent the neuronal substrates of reward processing during learning and established behavioral performance. The processing of reward expectations indicates access to central representations of rewards, which could be used for the neuronal control of goal-directed behavior.