Sensory and motor contents are prioritized dynamically in working memory

Internal selective attention prioritizes both sensory and motor contents in working memory to guide prospective behavior. Prior research has shown how attention modulation of sensory contents is flexible and temporally tuned depending on access requirements, but whether the prioritization of motor contents follows similar flexible dynamics remains elusive. Also uncharted is the degree of co-dependence of sensory and motor modulation, which gets at the nature of both working-memory representations and internal attention functions. To address these questions, we independently tracked the prioritization of sensory and motor working-memory contents as a function of dynamically evolving temporal expectations in human participants. The design orthogonally manipulated when an item location (left versus right side) and associated prospective action (left versus right hand) would be relevant. Contralateral-vs-ipsilateral modulation of posterior alpha (8-12 Hz) activity in electroencephalography (EEG) tracked prioritization of the item location, while contralateral-vs-ipsilateral modulation of central mu/beta (8-30 Hz) activity tracked response prioritization. Proactive and dynamic alpha and mu/beta modulation confirmed the flexible and temporally structured prioritization of sensory and motor contents alike. Intriguingly, the prioritization of sensory and motor contents was temporally uncoupled, showing dissociable patterns of modulation. The findings reveal multiple modulatory functions of internal attention operating in tandem to prepare relevant aspects of internal representations for adaptive behavior.