title: Effect of voluntary repetitive long-lasting muscle contraction activity on the BOLD signal as assessed by optimal hemodynamic response function.
abstract: OBJECTIVE
  Among other neuroimaging techniques, functional magnetic resonance imaging (fMRI) can be useful for studying the development of motor fatigue. The aim of this study was to identify differences in cortical neuronal activation in nine subjects on three motor tasks: right-hand movement with minimum, maximum, and post-fatigue maximum finger flexion.
  
  
  METHODS
  fMRI activation maps for each subject and during each condition were obtained by estimating the optimal model of the hemodynamic response function (HRF) out of four standard HRF models and an individual-based HRF model (ibHRF).
  
  
  RESULTS
  ibHRF was selected as the optimal model in six out of nine subjects for minimum movement, in five out of nine for maximum movement, and in eight out of nine for post-fatigue maximum movement. As compared to maximum movement, a large reduction in the total number of active voxels (primary sensorimotor area, supplementary motor area and cerebellum) was observed in post-fatigue maximum movement.
  
  
  CONCLUSIONS
  This is the first approach to the evaluation of long-lasting contraction effort in healthy subjects by means of the fMRI paradigm with the use of an individual-based hemodynamic response. The results may be relevant for defining a baseline in future studies on central fatigue in patients with neuropathological disorders.
authors.affiliation: Section of Neurology, Department of Neurological and Movement Sciences, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy, silviafrancesca.storti@univr.it.
authors.forename: Silvia Francesca
authors.initials: SF
authors.lastname: Storti
authors.forename: Emanuela
authors.initials: E
authors.lastname: Formaggio
authors.forename: Deborah
authors.initials: D
authors.lastname: Moretto
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bertoldo
authors.forename: Francesca Benedetta
authors.initials: FB
authors.lastname: Pizzini
authors.forename: Alberto
authors.initials: A
authors.lastname: Beltramello
authors.forename: Antonio
authors.initials: A
authors.lastname: Fiaschi
authors.forename: Gianna Maria
authors.initials: GM
authors.lastname: Toffolo
authors.forename: Paolo
authors.initials: P
authors.lastname: Manganotti
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014836:Volition / Q000502:physiology; D055815:Young Adult