Features Unbound: Spatial Resolution for Feature Binding is Impaired in Peripheral and Amblyopic Vision

We measured spatial resolution for discriminating targets that differed from nearby distractors in either color, orientation, or their conjunction. In the fovea of normal human observers, whenever both attributes are big enough to be individually visible, their conjunction is also visible. In the periphery, the two attributes may be visible but their conjunction may be invisible. We found a similar impairment in resolving conjunctions for the fovea of deprived eyes of humans with abnormal visual development (amblyopia). These results are quantitatively explained by a model of primary visual cortex (V1) in which orientation and color maps are imperfectly registered, due to scatter noise in neuronal topographic wiring. Our results in persons with amblyopia indicate that the ability of the fovea to compensate for this poor co-registration is consolidated by visual experience during post-natal development.