Abstract
INTRODUCTION: Previous work has shown that perceptual bias towards visual stimuli paired with reward correlates with indices of individual variability, such as personality scores and activation of reward-related structures (eg. dopamine-releasing neurons in Substantia Nigra (SN)). Whether a similar correlation exists with respect to sensitivity to punishment, and how this influence is related with the reward-driven bias, is less clear. METHODS: Here, participants looked for categories of objects (people, cars, trees) in naturalistic scenes and received different types of motivational feedback (rewarding, neutral or punishing) for correctly detecting these objects. Importantly, accurate task performance led in reward and punishment conditions to an equal financial benefit. At the same time, the two conditions presented opposite emotional valence for the subject, respectively garnering constant monetary gain or loss in spite of optimal performance. We subsequently looked at the representation of these stimuli in occipito-temporal object-selective cortex (OSC) using MVPA of fMRI data. RESULTS: We found that two measures of individual variability predicted the way in which stimuli paired with gain and loss were represented with respect to one another in OSC across subjects. On one hand, increased representation of rewarding stimuli was tracked in activity in the SN. On the other, increased representation of aversive stimuli was tracked in a personality questionnaire, the behavioural inhibition scale (BIS). Importantly, multiple linear regression showed that the contribution of these two variables was independent and additive. Two separate, but comparable, experiments garner equal results. CONCLUSIONS: These studies suggest that, across subjects, sensitivity to reward and to punishment separately contribute to the non-strategic prioritization of positively and negatively valenced stimuli with respect to each other.