title: Brief sleep after learning keeps emotional memories alive for years.
abstract: BACKGROUND
  Sleep after learning supports memory consolidation. However, long-lasting memory effects of sleep have not yet been investigated. Postlearning sleep may be particularly involved in the long-term retention of emotional memories and could thereby contribute to the development of posttraumatic stress disorder (PTSD), a disease thought to result from overconsolidation of traumatic memories.
  
  
  METHODS
  Subjects (healthy men) who had learned neutral and emotional texts immediately before sleeping or remaining awake for the subsequent 3 hours were recontacted after 4 years for long-term memory assessment (forced-choice recognition test).
  
  
  RESULTS
  Sleep following learning compared with wakefulness enhanced memory for emotional texts after 4 years (p = .001). No such enhancement was observed for neutral texts (p = .571).
  
  
  CONCLUSIONS
  Brief periods of sleep immediately following learning cause preservation of emotional memories over several years. Sleep deprivation in the immediate aftermath of traumatic events could be a promising therapeutic measure to prevent PTSD.
authors.affiliation: Department of Neuroendocrinology, Medical University of Lübeck, Lübeck, Germany. wagner@kfg.mu-luebeck.de
authors.forename: Ullrich
authors.initials: U
authors.lastname: Wagner
authors.forename: Manfred
authors.initials: M
authors.lastname: Hallschmid
authors.forename: Björn
authors.initials: B
authors.lastname: Rasch
authors.forename: Jan
authors.initials: J
authors.lastname: Born
mesh_terms: D016009:Chi-Square Distribution; D004644:Emotions / Q000502:physiology*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012016:Reference Values; D012153:Retention, Psychology / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D012892:Sleep Deprivation / Q000523:psychology; D013313:Stress Disorders, Post-Traumatic / Q000517:prevention & control* / Q000523:psychology; D013997:Time Factors