Probing the limits of activity-silent non-conscious working memory

Abstract

Significance Our work tackles a current debate regarding working memory (WM). Traditionally, this ability to maintain and manipulate information has been thought to require conscious processing and persistent neural activity. Recent evidence challenges this assumption: Information may be briefly stored without conscious awareness and sustained neural activity. Here, we reconcile these competing views. We recorded brain activity while adults remembered or mentally rotated subjectively visible or invisible stimuli. We showed that the mere short-term storage of information may proceed without consciousness or persistent neural activity. However, manipulating information in WM during rotation required both. Thus, non-conscious, activity-silent maintenance is a genuine phenomenon but should be termed “activity-silent short-term memory”; when using a memory, a reactivation, associated with conscious reportability, is necessary.