The role of working memory for bridging the gap between perception and goal-directed actions - Evidence by mu and beta oscillations in sensorimotor cortex

Abstract

What mechanisms are at work when transferring a visual representation in working memory into a higher-level code for guiding future actions? We investigated the underlying attentional and motor selection processes in working memory by means of oscillatory EEG parameters. Participants stored two, three or four objects in working memory and subsequent retroactive cues indicated one or two items as task-relevant. The oscillatory response in mu (10-14 Hz) and beta (15-25 Hz) frequencies with an estimated source in sensorimotor cortex contralateral to response side was used as a correlate of motor planning. There was a stronger suppression of oscillatory power when only one item was cued. Importantly, this effect appeared although the required response could not be anticipated at this point in time. This suggests that working memory can store multiple item-specific motor plans and the selection of a stored visual item leads to an automatic updating of associated response alternatives.