LAUSR

Our vision systems utilize attention to process dynamic visual information everyday. Multiple object tracking (MOT) is widely used for studying sustained attention in dynamic environments. Previous research reported inter-target grouping based on feature similarity (e.g., targets sharing the same color, size, or shape) can facilitate tracking. A recent study also found that symmetric relation among targets in MOT tasks can automatically improve tracking performance, and a greater grouping effect based on symmetry and feature was observed. However, grouping based on multiple feature cues didn't produce a greater grouping effect than grouping based on one feature cue. Why were groupings based on symmetry and feature additive, but two feature-based groupings were not? How stimulus-driven inter-target groupings based on color or symmetry improve the goal-directed target tracking process remains unknown. We hypothesized that symmetry-based and feature-based groupings would involve different cortical and subcortical areas, and color-based and color-shape-based groupings would be manifested in significant activity in the same regions. This study used functional magnetic resonance imaging (fMRI) to identify cortical and subcortical areas involved in feature-based and symmetry-based groupings respectively during tracking. The results of our experiment showed that lateral occipital (LO) cortex is involved in symmetry-based grouping during tracking. Bilateral putamen, temporal parietal junction (TPJ), and frontal eye field (FEF) are involved in the feature-based grouping. Our findings likely indicate that stimulus-driven inter-target symmetry-based grouping and feature-based grouping improve goal-directed target tracking in different ways.