Alpha-band desynchronization reflects memory-specific processes during visual change detection

Recent work investigating physiological mechanisms of working memory (WM) has revealed that modulation of alpha and beta frequency bands within the EEG plays a key role in WM storage. However, the nature of that role is unclear. In the present study, we examined event-related desynchronization of alpha and beta (α/β-ERD) elicited by visual tasks with and without a memory component to measure the impact of a WM demand on this electrophysiological marker. We recorded EEG from 60 healthy participants while they completed three variants on a typical change detection task: one in which participants passively viewed the sample array, passive (WM-); one in which participants viewed and attended the sample array in search of a target color but did not memorize the colors, active (WM-); and one in which participants encoded, attended to, and memorized the sample array, active (WM+). Replicating previous findings, we found that active (WM+) elicited robust α/β-ERD in frontal and posterior electrode clusters and that α-ERD was significantly associated with WM capacity. By contrast, α/β-ERD was significantly smaller in the passive (WM-) and active (WM-) tasks, which did not consistently differ from one another. Furthermore, no such relationship was observed between WM capacity and desynchronization in the passive (WM-) or active (WM-) tasks. Taken together, these results suggest that α-ERD during memory formation reflects a memory-specific process such as consolidation or maintenance, rather than serving a generalized role in perceptual gating or engagement of attention.