Awake reactivation and suppression after brief task exposure depend on task novelty

Abstract

Previously learned information is known to be reactivated during periods of quiet wakefulness and such awake reactivation is considered to be a key mechanism for memory consolidation. We recently demonstrated that feature-specific awake reactivation occurs in early visual cortex immediately after extensive visual training on a novel task. To understand the exact role of awake reactivation, here we investigated whether such reactivation depends specifically on the task novelty. Subjects completed a brief visual task that was either novel or extensively trained on previous days. Replicating our previous results, we found that awake reactivation occurs for the novel task even after a brief learning period. Surprisingly, however, brief exposure to the extensively trained task led to \"awake suppression\" such that neural activity immediately after the exposure diverged from the pattern for the trained task. Further, subjects who had greater performance improvement showed stronger awake suppression. These results suggest that the brain operates different post-task processing depending on prior visual training.