How visual working memory handles distraction: cognitive mechanisms and electrophysiological correlates

The ability to selectively encode relevant information (filtering ability) is crucial to make best use of the severely limited space that visual working memory (VWM) provides. This review considers why filtering ability is important, how it is measured, and it discusses how filtering might be implemented computationally at the cognitive and neuronal level. Based on theoretical considerations, we explore the possibility that filtering ability involves not only the suppression of irrelevant, but also the enhancement of relevant information – functions that might be implemented by different brain mechanisms; and we review behavioural and electrophysiological data in light of the various resulting model versions. We also highlight that filtering is better understood as coordinated brain network activity, rather than being the function of a single region. Broadcasting of control signals from prefrontal cortex appears critical in upholding information in posterior cortical areas in the absence of distractors. The very same ability might also support selective processing of relevant information in the presence of distractors. These ideas provide a novel explanation for the relation between filtering ability and VWM capacity and thereby (re-)establish a central role of filtering ability in general VWM functioning.