Electrophysiological Correlates of Cue-Related Processing in a Gambling Task: Early Outcome Evaluation or Outcome Expectation?

Several recent studies have suggested that cues that predict outcomes elicit a feedback-related-like negativity (FRN-like negativity) reflecting initial appraisals of whether desired outcomes are probable. Some other studies, however, have found that the cues that predict outcomes elicited event-related potentials (ERPs) that reflect the expectation to outcomes (e.g., outcome expectations). Given these mixed findings, this study aimed to examine whether the brain activity elicited by predictive cues in a gambling task reflected the initial evaluations of the outcomes, the outcome expectations, or both. We used a gambling task in which the participants were told to guess which of two doors hid a reward. At the beginning of each trial, a cue was presented to inform the participants of how many doors hid a reward. We found that these predictive cues elicited a FRN-like negativity at the frontal sites within around 200-300 ms. However, this negativity did not significantly differ between the cues that fully predicted gains and the cues that fully predicted losses. Furthermore, predictive cues elicited an expectation-related slow wave, and cues that predicted gains with a 50% probability elicited a larger expectation-related slow wave than cues that fully predicted gains or losses. Our results suggest that cues predicting outcomes reflect outcome expectations rather than initial evaluations of the forthcoming outcomes.