Memory Consolidation in Sleep: Dream or Reality

Neuron Volume 44, Issue 1, 30 September 2004, Pages 135-148
Review

Memory Consolidation in Sleep: Dream or Reality

Robert P. Vertes Corresponding Author Contact Information, a, E-mail The Corresponding Author

aCenter for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431 USA

Available online 29 September 2004.

Abstract

We discuss several lines of evidence refuting the hypothesis that procedural or declarative memories are processed/consolidated in sleep. One of the strongest arguments against a role for sleep in declarative memory involves the demonstration that the marked suppression or elimination of REM sleep in subjects on antidepressant drugs or with brainstem lesions produces no detrimental effects on cognition. Procedural memory, like declarative memory, undergoes a slow, time-dependent period of consolidation. A process has recently been described wherein performance on some procedural tasks improves with the mere passage of time and has been termed “enhancement.” Some studies, but not others, have reported that the consolidation/enhancement of perceptual and motor skills is dependent on sleep. We suggest that consolidation or enhancement, initiated in waking with task acquisition, could in some instances extend to sleep, but sleep would serve no unique role in these processes. In sum, there is no compelling evidence to support a relationship between sleep and memory consolidation.

Article Outline

Main Text

Introduction
A Revisiting of This Issue
General Considerations Relevant to the Current Debate

Mismatch between the Cognitive Content of Waking and Sleep
Sleep Is an Amnesiac State
Sleep Is Not Involved in Declarative Memory

Sleep Suppression/Elimination in Animals and Humans: Effects on Memory Processing and Consolidation

Animal Studies
Human Studies
Brainstem Lesions
Antidepressant Drugs

Memory Consolidation, Procedural Memory, and Sleep
Procedural Memory and Time- Dependent Consolidation

Unresolved Issues

“Replay” of Patterns of Neural Activity of Waking in Subsequent Sleep in Animals
Other Factors
What Is the Function of Sleep/REM Sleep?
Summary and Conclusions

Acknowledgements
References