Brief sleep after learning keeps emotional memories alive for years.
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.
Wagner
Ullrich
U
Department of Neuroendocrinology, Medical University of Lübeck, Lübeck, Germany. wagner@kfg.mu-luebeck.de
Hallschmid
Manfred
M
Rasch
Björn
B
Born
Jan
J
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