Abstract
Visual working memory (VWM) constructs stable internal representations over time and allows us to update these representations. It has been demonstrated that visual representations stored in VSTM have been successfully reconstructed or decoded from measurements of neural activity. Using electroencephalography (EEG), recent studies have reported that the power of alpha-band oscillations can reveal the spatial location of remembered items. However, it is not clear whether alpha power carries information about the orientation of remembered items. In addition, it is unclear whether the updated representations in VWM are reflected in the neural signals. Here we address the nature of neural signals that carry updated orientation information by asking how EEG amplitudes and the power of oscillations are associated with visual representations. In the task, participants were shown a Gabor and then given a cue to mentally rotate the Gabor 1) clockwise, 2) counter-clockwise, or 3) not at all. We reconstructed the perceptual information (presented orientation) and mnemonic information (reported orientation) from alpha oscillations (8-12 Hz). We were able to reconstruct both the presented orientation across conditions from alpha amplitude, but not from alpha power. Furthermore, we were able to reconstruct the reported orientation, suggesting that the neural signals carry the updated memory representations as well as the sensory information. The current study indicates that the amplitude of EEG signals serves an important role for conveying orientation specific information that is lost in the conversion to estimating power.