Instructed delay activity in the human prefrontal cortex is modulated by monetary reward expectation

Goal-directed actions are executed with greater efficiency when the goals of the actions are rewarded and so the reward expectation must influence systems concerned with action-planning and motor control. However, little is known about how this influence is achieved in primates. Here, we demonstrate in human subjects that manual performance is enhanced when the goals of the visually cued actions are monetary rewards. We also used event-related fMRI in the same subjects to localize neural activity related to action preparation and selection that was influenced by the reward. We found three areas with significant interaction between reward and preparation: the prestriate visual cortex, the premotor cortex and the lateral prefrontal cortex. The latter two areas appear to be frontal systems integrating the expectation of rewards with selection and preparation of actions.