title: No Associations between Interindividual Differences in Sleep Parameters and Episodic Memory Consolidation.
abstract: OBJECTIVE
  Sleep and memory are stable and heritable traits that strongly differ between individuals. Sleep benefits memory consolidation, and the amount of slow wave sleep, sleep spindles, and rapid eye movement sleep have been repeatedly identified as reliable predictors for the amount of declarative and/or emotional memories retrieved after a consolidation period filled with sleep. These studies typically encompass small sample sizes, increasing the probability of overestimating the real association strength. In a large sample we tested whether individual differences in sleep are predictive for individual differences in memory for emotional and neutral pictures.
  
  
  METHODS
  Between-subject design.
  
  
  METHODS
  Cognitive testing took place at the University of Basel, Switzerland. Sleep was recorded at participants' homes, using portable electroencephalograph-recording devices.
  
  
  METHODS
  Nine hundred-twenty-nine healthy young participants (mean age 22.48 ± 3.60 y standard deviation).
  
  
  METHODS
  None.
  
  
  RESULTS
  In striking contrast to our expectations as well as numerous previous findings, we did not find any significant correlations between sleep and memory consolidation for pictorial stimuli.
  
  
  CONCLUSIONS
  Our results indicate that individual differences in sleep are much less predictive for pictorial memory processes than previously assumed and suggest that previous studies using small sample sizes might have overestimated the association strength between sleep stage duration and pictorial memory performance. Future studies need to determine whether intraindividual differences rather than interindividual differences in sleep stage duration might be more predictive for the consolidation of emotional and neutral pictures during sleep.
authors.affiliation: Department of Psychology, Division of Molecular Neuroscience, University of Basel, CH-4055 Basel, Switzerland.|Department of Psychology, Division of Biopsychology, University of Zurich, CH-8050 Zurich, Switzerland.|Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, CH-8032 Zurich, Switzerland.
authors.forename: Sandra
authors.initials: S
authors.lastname: Ackermann
authors.affiliation: Department of Psychology, Division of Molecular Neuroscience, University of Basel, CH-4055 Basel, Switzerland.
authors.forename: Francina
authors.initials: F
authors.lastname: Hartmann
authors.affiliation: Department of Psychology, Division of Molecular Neuroscience, University of Basel, CH-4055 Basel, Switzerland.|Department Biozentrum, Life Sciences Training Facility, University of Basel, CH-4056 Basel, Switzerland.|Psychiatric University Clinics, University of Basel, CH-4012 Basel, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Papassotiropoulos
authors.affiliation: Psychiatric University Clinics, University of Basel, CH-4012 Basel, Switzerland.|Department of Psychology, Division of Cognitive Neuroscience, University of Basel, CH-4055 Basel, Switzerland.
authors.forename: Dominique J-F
authors.initials: DJ
authors.lastname: de Quervain
authors.affiliation: Department of Psychology, Division of Biopsychology, University of Zurich, CH-8050 Zurich, Switzerland.|Department of Psychology, Cognitive Biopsychology and Methods, University of Fribourg, CH-1701 Fribourg, Switzerland.
authors.forename: Björn
authors.initials: B
authors.lastname: Rasch
mesh_terms: D000293:Adolescent; D000328:Adult; D004569:Electroencephalography; D004644:Emotions; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D061212:Memory, Episodic; D008954:Models, Biological; D010775:Photic Stimulation; D010781:Photography; D015203:Reproducibility of Results; D018401:Sample Size; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D013557:Switzerland; D013997:Time Factors; D055815:Young Adult
keywords: declarative memory; rapid eye movement sleep; sample size; sleep EEG; slow wave sleep