title: Rapid eye movement and non-rapid eye movement sleep contributions in memory consolidation and resistance to retroactive interference for verbal material.
abstract: OBJECTIVE
  To test the hypothesis that rapid eye movement (REM) sleep contributes to the consolidation of new memories, whereas non-rapid eye movement (NREM) sleep contributes to the prevention of retroactive interference.
  
  
  METHODS
  Randomized, crossover study.
  
  
  METHODS
  Two sessions of either a morning nap or wakefulness.
  
  
  METHODS
  Twenty-five healthy young adults.
  
  
  METHODS
  Declarative learning of word pairs followed by a nap or a wake interval, then learning of interfering word pairs and delayed recall of list A.
  
  
  RESULTS
  After a restricted night (24:00-06:00), participants learned a list of word pairs (list A). They were then required to either take a nap or stay awake during 45 min, after which they learned a second list of word pairs (list B) and then had to recall list A. Fifty percent of word pairs in list B shared the first word with list A, resulting in interference. Ten subjects exhibited REM sleep whereas 13 subjects exhibited NREM stage 3 (N3) sleep. An interference effect was observed in the nap but not in the wake condition. In post-learning naps, N3 sleep was associated with a reduced interference effect, which was not the case for REM sleep. Moreover, participants exhibiting N3 sleep in the post-learning nap condition also showed a reduced interference effect in the wake condition, suggesting a higher protection ability against interference.
  
  
  CONCLUSIONS
  Our results partly support the hypothesis that non-rapid eye movement sleep contributes in protecting novel memories against interference. However, rapid eye movement sleep-related consolidation is not evidenced.
authors.affiliation: UR2NF - Neuropsychology and Functional Neuroimaging Research Group at CRCN - Center for Research in Cognition and Neurosciences, Université Libre de Bruxelles (ULB) and UNI - ULB Neurosciences Institute; Brussels, Belgium ; Sleep Laboratory & Unit for Chronobiology U78, Brugmann University Hospital - Université Libre de Bruxelles (U.L.B./V.U.B.), Brussels, Belgium.
authors.forename: Gaétane
authors.initials: G
authors.lastname: Deliens
authors.forename: Rachel
authors.initials: R
authors.lastname: Leproult
authors.forename: Daniel
authors.initials: D
authors.lastname: Neu
authors.forename: Philippe
authors.initials: P
authors.lastname: Peigneux
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D017286:Polysomnography; D012892:Sleep Deprivation / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology*; D014706:Verbal Learning / Q000502:physiology*
keywords: Declarative learning; memory consolidation; nap; retroactive interference; sleep stages