What is the functional role of delay-related alpha oscillations during working memory?

“Activity-silent” working memory (WM) has been proposed as an energy-efficient short-term storage mechanism that does not require persistent spiking. Previously we developed a novel experimental approach to test its key predictions and showed that an external perturbation results in a subtle but reliable readout of the information in WM, even for unattended memories that otherwise do not exhibit persistent neural activity during maintenance. More recently, there has been intense interest in what differentiates attended and unattended items in WM, with diverse suggestions ranging from storage in different brain areas, reversed neural codes or that both are stored in low-frequency oscillatory activity. Here we specifically consider this latter suggestions, as proposed by Barbosa et al. based on their secondary analysis of our freely available EEG data. We are pleased that our previously published data have contributed to new and potentially important findings, but we also note that this oscillatory correlate raises further questions, and does not necessarily disqualify activity-silent models of WM.