title: Short Sleep Makes Declarative Memories Vulnerable to Stress in Humans.
abstract: OBJECTIVE
  This study sought to investigate the role of nocturnal sleep duration for the retrieval of oversleep consolidated memories, both prior to and after being cognitively stressed for ∼30 minutes the next morning.
  
  
  METHODS
  Participants learned object locations (declarative memory task comprising 15 card pairs) and a finger tapping sequence (procedural memory task comprising 5 digits) in the evening. After learning, participants either had a sleep opportunity of 8 hours (between ∼23:00 and ∼07:00, full sleep condition) or they could sleep between ∼03:00 and ∼07:00 (short sleep condition). Retrieval of both memory tasks was tested in the morning after each sleep condition, both before (∼08:30) and after being stressed (∼09:50).
  
  
  METHODS
  Sleep laboratory.
  
  
  METHODS
  15 healthy young men.
  
  
  RESULTS
  The analyses demonstrated that oversleep memory changes did not differ between sleep conditions. However, in their short sleep condition, following stress hallmarked by increased subjective stress feelings, the men were unable to maintain their pre-stress performance on the declarative memory task, whereas their performance on the procedural memory task remained unchanged. While men felt comparably subjectively stressed by the stress intervention, overall no differences between pre- and post-stress recalls were observed following a full night of sleep.
  
  
  CONCLUSIONS
  The findings suggest that 8-h sleep duration, within the range recommended by the US National Sleep Foundation, may not only help consolidate newly learned procedural and declarative memories, but also ensure full access to both during periods of subjective stress.
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cedernaes
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Frida H
authors.initials: FH
authors.lastname: Rångtell
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Emil K
authors.initials: EK
authors.lastname: Axelsson
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Adine
authors.initials: A
authors.lastname: Yeganeh
authors.affiliation: Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Heike
authors.initials: H
authors.lastname: Vogel
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Jan-Erik
authors.initials: JE
authors.lastname: Broman
authors.affiliation: Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: Dickson
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Helgi B
authors.initials: HB
authors.lastname: Schiöth
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Benedict
mesh_terms: D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D012892:Sleep Deprivation / Q000503:physiopathology*; D013315:Stress, Psychological / Q000503:physiopathology*; D055815:Young Adult
keywords: cognitive stress; oversleep memory consolidation; sleep duration