Attentional guidance through object associations in visual cortex

Abstract

Efficient behavior requires the rapid attentional selection of task-relevant objects. Previous research has shown that target-selective neurons in visual cortex increase their baseline firing rate when participants are cued to search for a target object. Such preparatory activity represents a key finding for theories of visual search, as it may reflect a top-down bias that guides spatial attention, favoring processing of target-matching input for subsequent report. However, in daily life, visual search is often guided by non-target objects that are neither externally cued nor reported. For instance, when looking for a pen, we may direct our attention to the office desk where we expect the pen to be. These 'anchor objects' (e.g., the desk) thereby guide search for associated objects (e.g., the pen) in scenes. Here, we used fMRI and eye tracking to test whether preparatory activity during visual search represents the target (the pen), the guiding anchor object (the desk) or both. In an anchor-guided search task, participants (N=34) learned associations between targets and anchors and searched for these targets in scenes. To fully dissociate target from anchor processing, target-anchor associations were reversed across different scene contexts. Participants' first fixations were reliably guided towards the target-associated anchor. Importantly, preparatory fMRI activity patterns in lateral occipital cortex (LOC) represented the target-associated anchor rather than the target. Whole-brain analyses additionally identified a region in the right intraparietal sulcus that represented the anchor. Our results show that preparatory activity in visual cortex represents a self-generated guiding template, supporting visual search in structured daily-life environments.