Amblyopic adults demonstrate intact endogenous spatial attention
63.4030, Wednesday, 20-May, 8:30 am - 12:30 pm, Pavilion
Mariel Roberts1, Marisa Carrasco1,2; 1Department of Psychology, New York University, 2Center for Neural Science, New York University
Background. Amblyopia is a developmental disorder characterized by a wide array of visual deficits following abnormal binocular childhood experience. Neuroimaging and behavioral studies have argued that amblyopia results in abnormal allocation of endogenous attention, but none have directly manipulated it and assessed its perceptual consequences. In visually-intact adults, endogenous attention increases performance in orientation discrimination tasks mediated by contrast sensitivity. Purpose: We explored whether and how the modulatory effects of endogenous attention on orientation discrimination differ (1) between the eyes of amblyopic adults and (2) compared to the corresponding eyes of visually-intact controls. Methods. 11 amblyopic (7-strabismic; 4-anisometropic) and 11 age- and gender-matched control adults were monocularly tested on a 2-AFC orientation discrimination task. Four Gabor patches (independently and randomly tilted ±20° from vertical) appeared at isoeccentric diagonal locations. Participants were presented with a central precue (60% valid; 20% invalid; 20% neutral) indicating the possible target location(s). In the valid condition, precue and postcue locations matched, in the invalid condition they did not. Stimulus contrast was adjusted in the neutral condition to equate task difficulty between eyes within observers and across observers. Results. In both groups, deployment of endogenous attention resulted in a significant performance benefit (valid–neutral condition) and cost (neutral–invalid condition). The magnitudes of these effects did not differ between the two eyes within each group or between the groups. RT analysis followed the same pattern of results, ruling out speed-accuracy tradeoffs. Conclusions. Despite their characteristic low-level vision impairments, endogenous attention remains functionally intact in human amblyopic adults. This finding, in conjunction with studies of exogenous attention in amblyopic human adults (Carrasco et al., VSS 2014) and of endogenous attention with amblyopic monkeys (Kiorpes et al., VSS 2014), show that covert attention is intact in amblyopes.