Top-down selection of visual working memory contents is supported by alpha-band phase-synchronized oscillatory networks

Visual working memory (VWM) maintenance depends on oscillatory network dynamics across multiple frequency bands throughout fronto-parietal and sensory brain areas. However, whether these networks reflect the active maintenance of visual information content or serve top-down control processes, has remained unresolved. To address this, we used concurrent magneto- and electroencephalography (M/EEG) to measure brain activity during VWM tasks, in which the memory content was parametrically controlled. Using new edge-level analysis for source-connectivity networks, we disentangled connections and subnetworks underlying the maintenance of specific contents from those supporting feature-general VWM. We show here that long-range high-alpha band (α, 11–13 Hz) phase-synchronization networks carry out a dual role in these VWM functions. α-band subgraphs localized to the visual areas are feature-selective and maintain the contents of VWM. In contrast, the high α-band subgraph in the fronto-parietal areas was shared across memory contents, suggesting that it forms the content-agnostic executive core of VWM. We propose that α-band synchronization across distinct, but yet interconnected, subgraphs support the active maintenance of feature representations and their top-down selection.