Sleep, dreams, and memory consolidation: the role of the stress hormone cortisol

Learn Mem. Nov-Dec 2004;11(6):671-8. doi: 10.1101/lm.77104.


We discuss the relationship between sleep, dreams, and memory, proposing that the content of dreams reflects aspects of memory consolidation taking place during the different stages of sleep. Although we acknowledge the likely involvement of various neuromodulators in these phenomena, we focus on the hormone cortisol, which is known to exert influence on many of the brain systems involved in memory. The concentration of cortisol escalates over the course of the night's sleep, in ways that we propose can help explain the changing nature of dreams across the sleep cycle.

Publication types

  • Review

MeSH terms

  • Animals
  • Cerebral Cortex / physiology
  • Dreams / physiology*
  • Hippocampus / physiology*
  • Humans
  • Hydrocortisone / physiology*
  • Memory / physiology*
  • Neural Pathways / physiology
  • Neurotransmitter Agents / physiology
  • Sleep Stages / physiology*
  • Thinking / physiology


  • Neurotransmitter Agents
  • Hydrocortisone