title: Absence of haemodynamic refractory effects in patients with migraine without aura: an interictal fMRI study.
abstract: BACKGROUND
  In healthy controls, haemodynamic refractory effects are observed with blood-oxygenation-level dependent (BOLD) functional MRI (fMRI): the haemodynamic response function (HRF) to the second stimulus in a pair of stimuli with short interstimulus interval (ISI) shows a decreased amplitude and an increased time-to-peak. We hypothesize that there may be interictal haemodynamic abnormalities in migraineurs.
  
  
  METHODS
  An event-related fMRI design with paired face stimuli and varying ISIs was used to measure interictal HRFs in the face recognition area of patients with migraine without aura (MwoA) and controls. Net responses to the second stimulus in a pair were calculated and averaged per participant. Several characterizing parameters of the net responses were quantified and examined within each group.
  
  
  RESULTS
  Refractory effects were not observed in our patient group. There are no changes in the net responses compared with the reference situation in patients, irrespective of the ISI, whereas in controls all HRF parameters are decreased or delayed for an ISI of 1 second.
  
  
  CONCLUSIONS
  This is the first fMRI study investigating the haemodynamic refractory effects in MwoA patients. Unlike in controls, these effects are not observed in migraineurs. Although currently unclear, it is tempting to speculate that this observation reflects the neurovascular correlate of lack of habituation measured with evoked potentials in migraineurs.
authors.affiliation: Ghent University, Belgium. Benedicte.Descamps@UGent.be
authors.forename: Benedicte
authors.initials: B
authors.lastname: Descamps
authors.forename: Pieter
authors.initials: P
authors.lastname: Vandemaele
authors.forename: Harmen
authors.initials: H
authors.lastname: Reyngoudt
authors.forename: Karel
authors.initials: K
authors.lastname: Deblaere
authors.forename: Luc
authors.initials: L
authors.lastname: Leybaert
authors.forename: Koen
authors.initials: K
authors.lastname: Paemeleire
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020326:Migraine without Aura / Q000503:physiopathology*; D055815:Young Adult