Biasing visual selection: functional neuroimaging of the interplay between spatial cueing and feature memory guidance.

The authors investigate the interplay between spatial attention and memory-based feature guidance of visual selection. Three types of guidance were tested: working memory, spatial cueing and passive memory. In all cases the memory-cue was not relevant to a subsequent search task, whilst the spatial cue always provided valid information. Behaviourally, search performance was influenced by spatial cueing and by feature-based cueing from the contents of working memory; both forms of guidance interacted, with feature guidance being more effective when the target's location was not pre-cued. Spatial cueing recruited the dorsal fronto-parietal network which was silent during the WM-only condition. Memory guidance of selection was reflected in activity in a frontal-temporal-occipital network. Interestingly, when spatial and memory guidance were pitted against each other, neural activity in this latter network was greatly attenuated. Connectivity analysis showed that the posterior parietal cortices inhibit the responses of occipital and temporal regions to the onset of memory-items in the search display. In the presence of a reliable spatial cue the posterior parietal cortex resumes control of attentional deployment. These results illustrate how different forms of attention guidance interact to optimise visual selection.