Neural Mechanisms of Visuo-Spatial Attention in School-Aged Children

Abstract

Selective attention, the ability to focus on key information and filter out noise, is crucial for navigating the cluttered world. The neural basis of selective attention has been widely studied in the adult brain. However, much less is known about how selective attention operates and develops in children’s brain. Using neuroimaging, this dissertation investigates visuo-spatial selective attention in school children (ages 6 to 12). It employs a framework that is grounded in biased competition theory in order to probe each part of the neural mechanisms underlying selective attention functions. The first study demonstrates sensory competition in children’s visual cortex, providing a foundation for investigations of sensory-driven and goal-driven mechanisms that modulate the competition. The second study examines the extent to which children’s visual system can use perceptual grouping principles, as one of the sensory-driven mechanisms. Evidence suggests that perceptual grouping in visual cortex continues to refine beyond age 6, which could serve as a bottleneck for efficient selective processing. The third study shows that the fronto-parietal attention network, a source of goal-driven attention control, matures by achieving a balance between the two hemispheres. Using a perceptual line bisection task, it demonstrates that children in early elementary grades (ages 6 to 8) show an attention bias towards the left-hand side of space, which gradually diminishes and becomes adult-like by middle school ages (ages 11 to 13). It also shows that the degree of spatial bias is linked to functional connectivity patterns within each child’s attention network. Interestingly, such leftward biases in children are related to their reading fluency, suggesting an interaction between the attention network and the reading network across development. Together, this work demonstrates that the development of visuo-spatial selective attention in childhood is a dynamic process that is shaped by sensory processing and cognitive skills that continue to change throughout this age range. Interactions with perceptual functions and newly acquired cognitive skills should be addressed in order to better characterize the typical and atypical development of visuo-spatial selective attention.