From Bao et al., 2010 (their figure 3). a) Time course of the VEPs for trained versus untrained orientation, before and after training. The gray bars mark the latency for the early segment of the C1 component. b, c) Normalized peak amplitude for the trained orientation (TO) versus untrained orientation (UO) at the trained location (b) and untrained location (c). (Reproduced with permission of Society for Neuroscience: Bao, M., Yang, L., Rios, C., He, B., & Engel, S.A. (2010). Perceptual learning increases the strength of the earliest signals in visual cortex. The Journal of Neuroscience. 30, 15080-15084., Copyright 2010.)