Background: Amblyopia is a visual developmental disorder thought to affect 2.5 % of the population. Difficulties in processing form are common in children with amblyopia. Recent evidence has found that in addition to difficulties in processing form, children with amblyopia also have difficulties in processing motion that requires attention. This is demonstrated when children are asked to follow up to 4 moving target items from similar moving distractor items, and then to correctly locate the final position of those target items identified earlier (multiple object tracking, MOT). All children find it hard to track the items as the attentional demands of the task (the number of balls being tracked) increases. Yet, children with amblyopia do not perform as well as children without amblyopia, regardless of the number of items tracked. This may be attributed to functional differences at the posterior parietal cortex (PPC), an area higher up along the m/dorsal visual pathway that is responsible for successful attentive tracking.

Focus: I will use functional magnetic resonance imaging (fMRI) to examine a) functional differences of the PPC in children with and without amblyopia and b) the extent to which differences in PPC activity for children with amblyopia correlate with reduced performance of the MOT task.

Significance: Investigating the neural basis behind these deficits in attentive tracking can provide insight into how abnormalities in early development can affect the visual system and lead to the visual problems found in amblyopia. In turn, this may provide clues as to why occlusion therapy (otherwise known as eye patching), is effective for some children, while for others it is not. The overall goal of this line of research is to facilitate development of new and improved tools for diagnosis of amblyopia, and possibly lead to a re-evaluation of current standards of care.