title: Widespread changes in white matter microstructure after a day of waking and sleep deprivation.
abstract: BACKGROUND
  Elucidating the neurobiological effects of sleep and waking remains an important goal of the neurosciences. Recently, animal studies indicated that sleep is important for cell membrane and myelin maintenance in the brain and that these structures are particularly susceptible to insufficient sleep. Here, we tested the hypothesis that a day of waking and sleep deprivation would be associated with changes in diffusion tensor imaging (DTI) indices of white matter microstructure sensitive to axonal membrane and myelin alterations.
  
  
  METHODS
  Twenty-one healthy adult males underwent DTI in the morning [7:30AM; time point (TP)1], after 14 hours of waking (TP2), and then after another 9 hours of waking (TP3). Whole brain voxel-wise analysis was performed with tract based spatial statistics.
  
  
  RESULTS
  A day of waking was associated with widespread increases in white matter fractional anisotropy, which were mainly driven by radial diffusivity reductions, and sleep deprivation was associated with widespread fractional anisotropy decreases, which were mainly explained by reductions in axial diffusivity. In addition, larger decreases in axial diffusivity after sleep deprivation were associated with greater sleepiness. All DTI changes remained significant after adjusting for hydration measures.
  
  
  CONCLUSIONS
  This is the first DTI study of sleep deprivation in humans. Although previous studies have observed localized changes in DTI indices of cerebral microstructure over the course of a few hours, further studies are needed to confirm widespread DTI changes within hours of waking and to clarify whether such changes in white matter microstructure serve as neurobiological substrates of sleepiness.
authors.affiliation: Department of Psychosomatic Medicine, Institution of Oslo University Hospital, Oslo, Norway; Department of Neurology, Institution of Oslo University Hospital, Oslo, Norway; Norwegian Centre for Mental Disorders Research (NORMENT)/KG Jebsen Centre for Psychosis Research, Institution of Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Elvsåshagen
authors.affiliation: Department of Psychology, University of Oslo, Oslo, Norway.
authors.forename: Linn B
authors.initials: LB
authors.lastname: Norbom
authors.affiliation: Department of Psychosomatic Medicine, Institution of Oslo University Hospital, Oslo, Norway.
authors.forename: Per Ø
authors.initials: PØ
authors.lastname: Pedersen
authors.affiliation: Barnard College, Columbia University, New York, NY, United States of America.
authors.forename: Sophia H
authors.initials: SH
authors.lastname: Quraishi
authors.affiliation: The Intervention Centre, Institution of Oslo University Hospital, Oslo, Norway; Department of Physics (AB), University of Oslo, Oslo, Norway.
authors.forename: Atle
authors.initials: A
authors.lastname: Bjørnerud
authors.affiliation: Department of Psychosomatic Medicine, Institution of Oslo University Hospital, Oslo, Norway; Department of Research and Education, Institution of Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ulrik F
authors.initials: UF
authors.lastname: Malt
authors.affiliation: The Intervention Centre, Institution of Oslo University Hospital, Oslo, Norway; Department of Psychology, University of Oslo, Oslo, Norway.
authors.forename: Inge R
authors.initials: IR
authors.lastname: Groote
authors.affiliation: Norwegian Centre for Mental Disorders Research (NORMENT)/KG Jebsen Centre for Psychosis Research, Institution of Oslo University Hospital, Oslo, Norway; Department of Psychology, University of Oslo, Oslo, Norway.
authors.forename: Lars T
authors.initials: LT
authors.lastname: Westlye
mesh_terms: D000328:Adult; D056324:Diffusion Tensor Imaging; D006801:Humans; D008297:Male; D011859:Radiography; D012892:Sleep Deprivation / Q000000981:diagnostic imaging*; D013997:Time Factors; D016138:Walking; D066127:White Matter / Q000000981:diagnostic imaging*