The role of ventral striatum in reward-based attentional bias.

INTRODUCTION: Models of attention suggest that endogenous and exogenous factors can bias attention. However, recent data suggest that reward can also enhance attention towards relevant stimulus features as a function of involuntary biases. In this study, we utilized the additional singleton task to determine the neural circuitry that biases perceptual processing as a function of reward history.

METHODS: Participants searched for a unique shape amongst an array of differently shaped objects. All shapes, including the target shape, had the same color except one distractor shape. Participants randomly received a low or high reward after correct trials. From one trial to the next, target colors could stay the same or swap with the distractor color. Interestingly, and despite the irrelevancy of reward magnitude for task accuracy, the difference in reaction time between swap and non-swap trials usually is more pronounced following a high compared to a low reward.

RESULTS: In the current study, we showed that reward modulated attention is larger for individuals with enhanced reward magnitude sensitivity in the ventral striatum. In addition, connectivity data shows that ventral striatum was more positively connected with visual cortex during high reward non-swap trials compared to high reward swap trials for participants showing stronger reward modulated attention.

CONCLUSIONS: This suggests that involuntary reward modulated attention might be implemented by direct influences of the ventral striatum on visual cortex.