Bottom-Up and Top-Down Factors Differentially Influence Stimulus Representations Across Large-Scale Attentional Networks

Visual attention is thought to be supported by three large-scale frontoparietal networks: the frontoparietal control network (FPCN), the dorsal attention network (DAN), and the ventral attention network (VAN). The traditional view is that these networks support visual attention by biasing and evaluating sensory representations in visual cortical regions. However, recent evidence suggests that frontoparietal regions actively represent perceptual stimuli. Here, we assessed how perceptual stimuli are represented across large-scale frontoparietal and visual networks. Specifically, we tested whether representations of stimulus features across these networks are differentially sensitive to bottom-up and top-down factors. In a pair of pattern-based fMRI studies, male and female human subjects made perceptual decisions about face images that varied along two independent dimensions: gender and affect. Across studies, we interrupted bottom-up visual input using backward masks. Within studies, we manipulated which stimulus features were goal relevant (i.e., whether gender or affect was relevant) and task switching (i.e., whether the goal on the current trial matched the goal on the prior trial). We found that stimulus features could be reliably decoded from all four networks and, importantly, that subregions within each attentional network maintained coherent representations. Critically, the different attentional manipulations (interruption, goal relevance, and task switching) differentially influenced feature representations across networks. Whereas visual interruption had a relatively greater influence on representations in visual regions, goal relevance and task switching had a relatively greater influence on representations in frontoparietal networks. Therefore, large-scale brain networks can be dissociated according to how attention influences the feature representations that they maintain.