title: Structural gray matter abnormalities in migraine relate to headache lateralization, but not aura.
abstract: BACKGROUND
  The hallmark of migraine aura (MA) is transient cortical dysfunction but it is not known if MA is associated with structural cortical or subcortical changes. To determine the relation between MA and structural gray matter abnormalities, we studied a unique sample of 20 patients with frequent side-locked MA, i.e. visual aura consistently occurring in the same hemifield.
  
  
  METHODS
  We applied a highly sensitive within-patient design to assess anatomical differences with both voxel-based morphometry and surface-based morphometry on a whole-hemisphere level and for specific anatomical regions of interest. Within-subject comparisons were made with regard to aura symptoms (N = 20 vs 20) and with regard to headache (N = 13 vs 13).
  
  
  RESULTS
  We found no differences in gray matter structure with regard to aura symptoms in MA patients. Comparing the typical migraine headache side of the patients to the contralateral side revealed a difference in cortical thickness in the inferior frontal gyrus (mean difference 0.12 mm, p = 0.036).
  
  
  CONCLUSIONS
  MA per se is associated with abnormal function but not with lateralized abnormalities of gray matter structure. Alteration of the inferior frontal cortex suggests structural reorganization of pain inhibitory circuits in response to the repeated intense nociceptive input due to the headache attacks.
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Hougaard
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Faisal M
authors.initials: FM
authors.lastname: Amin
authors.affiliation: Visual Processing Laboratory, Ophthalmic Department, Otto-von-Guericke-University Magdeburg, Germany Center for Behavioral Brain Sciences, Germany.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Hoffmann
authors.affiliation: Functional Imaging Unit and Department of Radiology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Henrik B W
authors.initials: HB
authors.lastname: Larsson
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland.
authors.forename: Stefano
authors.initials: S
authors.lastname: Magon
authors.affiliation: Department of Neurology, University Hospital Basel, Switzerland Division of Neuroradiology, Department of Radiology, University Hospital Basel, Switzerland.
authors.forename: Till
authors.initials: T
authors.lastname: Sprenger
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark ashina@dadlnet.dk.
authors.forename: Messoud
authors.initials: M
authors.lastname: Ashina
mesh_terms: D000328:Adult; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D066128:Gray Matter / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020325:Migraine with Aura / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
keywords: Migraine; aura; brain structure; magnetic resonance imaging