Task-specific preparatory neural activations in low-interference contexts

How the brain prepares for forthcoming events is a pivotal question in human neuroscience. In the last years, several studies have suggested that expectations of perceiving upcoming stimuli engage relevant perceptual areas. Similarly, some experiments manipulating the task to be performed with targets have also found pre-activations in task-related brain areas. However, the usual configuration of this type of paradigms entails high levels of interference and/or working memory load, together with a small set of target stimuli. We designed a cued task paradigm in which interference was reduced to a minimum, as evidenced by behavioral indices of performance, and that included a high number of targets to avoid their anticipation. This was achieved using a large set of univalent target stimuli preceded by fully valid cues in a functional magnetic resonance imaging experiment. We found category-specific patterns of activity in which semantic cues engaged the left inferior frontal gyrus whereas spatial cues preactivated the right superior parietal lobe. Together with functional connectivity analyses, the activation maps showed the specific involvement of semantic and spatial processes upon the presentation of the cues that are coherent with previous literature. Our results thus suggest that even in contexts of low interference that prevent the anticipation of specific targets, our brain takes advantage of current information to deal with upcoming demands.