A link between perceptual learning, adaptation and sleep

Between-sessions gains in the texture discrimination task have been attributed to memory consolidation. A strong dependence of consolidation on sleep was suggested though not always supported by experimental results. Here we suggest that the interaction between consolidation and sleep depends on the adaptation level obtained during the training session. We find that both discrimination thresholds and learning depend on the number of trials used during training, with more trials producing higher discrimination thresholds due to suppressive processes related to adaptation. In addition, while learning benefits from increasing number of trials, a further increase in number of trials reduces learning. Consolidation may benefit from between-session sleep in the adapted states. (c) 2006 Elsevier Ltd. All rights reserved.