Response to Anticipated Reward in the Nucleus Accumbens Predicts Behavior in an Independent Test of Honesty

A, B, Task sequence of MID task (A) and coin-flip task (B). In the MID task (A), the subject observes the trial's monetary value, followed by a variable-duration fixation cross. After the fixation cross, a target square is briefly presented. The subject presses a button while the square is on the screen to get a financial reward or to avoid a financial loss. A feedback message with current and cumulative winnings/losses is presented. This is followed by a fixation interval. In the coin-flip task (B), the subject observes the trial's monetary value and privately predicts the outcome of the upcoming coin-flip. The subject records this prediction by pressing one of two buttons (No-Opportunity condition) or presses one of these buttons randomly (Opportunity condition). The subject then observes the outcome of the coin-flip. The subject then indicates whether the prediction was accurate and observes the amount of money won/lost based on the recorded prediction (No-Opportunity) or the self-reported accuracy (Opportunity). This is followed by a fixation interval.