Negative Reinforcement Impairs Overnight Memory Consolidation

Abstract

It is increasingly recognized that sleep following learning is beneficial for human memory performance. However, not all memories benefit equally from sleep. Here, we asked whether enhancing the salience of a learning task would augment overnight memory consolidation of a 3-D task. Our prior work has demonstrated that consolidation of this spatial memory task is associated with dreaming of the task (1). Thus, we additionally expected that enhanced task processing during sleep would increase the degree to which participants reported dreaming about the learning task. In the present study, we manipulated task salience by adding two specific manipulations to the maze – a monetary reward (Reward) and an audio performance feedback (Feedback). Contrary to our hypothesis, we found that Reward impaired overnight learning of the task. Feedback on the other hand, increased slow wave sleep (SWS), which was associated with a significant improvement in performance measures. Given the nature of the Reward version of the task, it appears that this feature may have actually induced more stress than motivation and therefore impaired learning in a cortisol-dependent mechanism.