Decoupling Orientation Specificity from Perceptual Learning in Amblyopic Vision

Abstract

Perceptual learning (PL) improves visual functions in amblyopes, but this learning is often specific to the trained orientation, possibly implying neural plasticity in the amblyopic early visual cortex. However, orientation specificity in normal vision can be decoupled from PL with a training-plus-exposure (TPE) technique (Zhang et al., 2010 Journal of Neuroscience30 12323–12328), suggesting PL occurs in higher brain areas. Here we used the TPE in adults with amblyopia to investigate whether PL reflects V1 plasticity or improved high-level decision making in the amblyopic brain. Our results demonstrate that: (1) PL of contrast discrimination in the fovea of amblyopic eyes (AEs) did not transfer to an orthogonal orientation. However, AEs were then exposed to the orthogonal orientation through irrelevant orientation discrimination training, which enabled contrast learning to transfer to the orthogonal orientation. (2) We found similar transfer in the AEs after the non-amblyopic eyes (NAEs) were exposed. (3)...