Distinct mechanisms underlie value-driven modulation of visual cortex by previously rewarded visual and auditory stimuli

Abstract

Past reward associations may be signaled by stimuli from different sensory modalities, however it remains unclear how different types of reward-associated stimuli modulate perception. In this human fMRI study, we employed a paradigm involving a visual discrimination task, where a visual target was simultaneously presented with either an intra- (visual) or a cross-modal (auditory) cue that was previously associated with rewards. We hypothesized that depending on the sensory modality of the cues distinct neural pathways underlie the value-driven modulation of visual areas. Two steps of analyses were conducted: first, using a multivariate approach, we confirmed that previously reward-associated cues enhanced the target representation in the early visual areas. Then, using effective connectivity analysis, we tested three possible patterns of communication across the brain regions that could underlie the modulation of visual cortex: a direct pathway from the frontal valuation areas to the visual areas, a mediated pathway through the attention-related areas, and a mediated pathway that additionally involved distinct sensory association areas for auditory and visual rewards. We found evidence for the third model and demonstrate that reward-related information is communicated across the valuation and attention-related brain regions such as the intraparietal sulcus across for both visual and auditory cues. Additionally, the long-range communication of reward information also involved the superior temporal areas in case of auditory reward-associated stimuli. These results suggest that in the presence of previously rewarded stimuli from different sensory modalities, a combination of domain-general and domain-specific mechanisms are recruited across the brain to adjust visual processing.