Abstract
Previous brain imaging studies have demonstrated that perceptual learning could enhance the representation of visual features in human early visual cortex. In this study, we used functional magnetic resonance imaging (fMRI) to investigate how perceptual learning could change the representation of face view in human visual system. We trained subjects to discriminate face orientations around a face side view (e.g. 30 deg) over eight days, which resulted in a dramatic improvement in sensitivity to face view orientation. This improved sensitivity was highly specific to the trained face side view. Before and after training, subjects were scanned to measure their brain responses (BOLD signal) to both the trained face view and untrained face views. We analyzed BOLD signals from cortical areas throughout the visual hierarchy, including early and middle-level visual areas (V1, V2, V3 and V4), occipital face area (OFA), superior temporal sulcus (STS) and fusiform face area (FFA). We found that, relative to untrained face views, BOLD signals in FFA and STS (but not other areas) to the trained face view significantly increased after the training on face view orientation discrimination, which was parallel to the psychophysical result. Our data suggest that the enhanced representation of a face view in higher visual areas could subserve our perceptual ability to discriminate face orientations around the face view.
National Natural Science Foundation of China (Project 30870762, 90920012 and 30925014).