title: Regional differences of [(18)F]-FDG uptake within the brain during fatiguing muscle contractions.
abstract: OBJECTIVE
  Many studies have shown that a position task is more difficult than a force task although both are performed at a similar net muscle force. Thus, the time to task failure is consistently shown to be briefer during the position task. The contributions of the central nervous system to these two types of fatiguing contractions are not completely understood. The purpose of this pilot study was to examine differences in regional brain activity between force and position tasks using positron emission tomography (PET) with [(18)F]-Fluorodeoxyglucose (FDG).
  
  
  METHODS
  Two participants performed both a force and position task, separated by 7 days, with the elbow flexor muscles at 15% maximal voluntary contraction force. During both tasks, each participant was injected with ≈ 256 (SD 11) MBq of FDG. Immediately after both tasks PET imaging was performed and images were analyzed to determine FDG uptake within regions of the brain.
  
  
  RESULTS
  FDG uptake was greater in the occipital and temporal cortices of the brain during the position task compared to the force task.
  
  
  CONCLUSIONS
  These findings suggest that differences in visual-spatial feedback and processing may play a role in the reduced time to failure of position tasks. Future application of these findings may lead to improved designs of rehabilitative strategies involving different types of visual feedback.
authors: Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado.
authors: John H
authors: JH
authors: Kindred
authors: Turku PET Centre, University of Turku and Turku University Hospital Turku, Finland.
authors: Kari K
authors: KK
authors: Kalliokoski
authors: Department of Physical Performance, Norwegian School of Sport Sciences Oslo, Norway.
authors: Jens
authors: J
authors: Bojsen-Møller
authors: Department of Health and Exercise Science, Colorado State University Fort Collins, Colorado.
authors: Thorsten
authors: T
authors: Rudroff
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: [18F]-Fluorodeoxyglucose; performance fatigability; positron emission tomography (PET); skeletal muscle fatigue; statistical parametric mapping (SPM)