title: Differential effects of duration of sleep fragmentation on spatial learning and synaptic plasticity in pubertal mice.
abstract: OBJECTIVE
  To examine the differential effects of acute and chronic sleep fragmentation (SF) on spatial learning and memory, and hippocampal long-term potentiation (LTP) in pubertal mice.
  
  
  METHODS
  Two studies were performed during which adolescent C57/Bl6 mice were subjected to acute-SF 24h a day × 3 days or chronic-SF for 12h a day × 2 weeks using a programmable rotating lever that provides tactile stimulus with controls housed in similar cages. Spatial learning and memory was examined using the Morris water maze, and long-term potentiation (LTP) was evaluated after stimulation of Schaffer collaterals in CA1 hippocampus post SF. Actigraphy was used during the period of SF to monitor rest-activity patterns. Electroencephalographic (EEG) recordings were acquired for analysis of vigilance state patterns and delta-power. Serum corticosterone was measured to assess stress levels.
  
  
  RESULTS
  Acute-SF via tactile stimulation negatively impacted spatial learning, as well as LTP maintenance, compared to controls with no tactile stimulation. While actigraphy showed significantly increased motor activity during SF in both groups, EEG data indicated that overall sleep efficiency did not differ between baseline and SF days, but significant increases in number of wakeful bouts and decreases in average NREM and REM bout lengths were seen during lights-on. Acute sleep fragmentation did not impact corticosterone levels.
  
  
  CONCLUSIONS
  The current results indicate that, during development in pubertal mice, acute-SF for 24h a day × 3 days negatively impacted spatial learning and synaptic plasticity. Further studies are needed to determine if any inherent long-term homeostatic mechanisms in the adolescent brain afford greater resistance to the deleterious effects of chronic-SF.
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Eli
authors.initials: E
authors.lastname: Wallace
authors.affiliation: Barrow Neurological Institute/St Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
authors.forename: Do Young
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Barrow Neurological Institute/St Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
authors.forename: Kye-Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Barrow Neurological Institute/St Joseph's Hospital and Medical Center, Phoenix, AZ, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Chen
authors.affiliation: Arizona State University, Tempe, AZ, USA; Arizona Alzheimer's Consortium, Phoenix, AZ, USA.
authors.forename: B
authors.initials: B
authors.lastname: Blair Braden
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Williams
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Kalene
authors.initials: K
authors.lastname: Jasso
authors.affiliation: Arizona State University, Tempe, AZ, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Garcia
authors.affiliation: Departments of Pediatrics and Clinical Neurosciences, University of Calgary Faculty of Medicine, Calgary, Canada.
authors.forename: Jong M
authors.initials: JM
authors.lastname: Rho
authors.affiliation: Arizona State University, Tempe, AZ, USA; Arizona Alzheimer's Consortium, Phoenix, AZ, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Bimonte-Nelson
authors.affiliation: University of Wisconsin School of Medicine and Public Health, Madison, WI, USA. Electronic address: maganti@neurology.wisc.edu.
authors.forename: Rama
authors.initials: R
authors.lastname: Maganti
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000503:physiopathology; D003345:Corticosterone / Q000097:blood; D004558:Electric Stimulation; D004569:Electroencephalography; D004576:Electromyography; D006128:Growth; D006624:Hippocampus / Q000503:physiopathology; D017774:Long-Term Potentiation; D008297:Male; D008568:Memory / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity; D012892:Sleep Deprivation / Q000503:physiopathology* / Q000523:psychology*; D065853:Spatial Learning / Q000502:physiology*
chemical_list: D003345:Corticosterone
keywords: Adolescence; LTP; Mice; Morris water maze; Sleep fragmentation; Spatial memory