title: [Neurophysiological evaluation of cortical excitability in migraine: a review of the literature].
abstract: BACKGROUND
  Neurophysiological studies point to altered cortical neuronal excitability in migraine patients.
  
  
  BACKGROUND
  Between attacks, migraine brain seems to be "hyperresponsive" to repetitive stimuli, as suggested by evoked potential studies that show a lack of habituation to sensory stimuli. Transcranial magnetic stimulation suggests an impairment of intracortical inhibitory circuits in migraine, especially in migraine with aura. Controversial results are obtained in migraineurs without aura. Repetitive transcranial magnetic stimulation also shows in migraine with aura a paradoxical enhancement of intracortical facilitation by low frequency stimulation and greater increased facilitatory mechanisms by high-frequency stimulation. Importantly, cortical excitability level fluctuates over time in relation to the migraine cycle. The interictal lack of habituation to sensory stimuli normalizes before and during a migraine attack. Changes of cortical excitability consistent with the theory of cortical spreading depression are also observed during migraine aura with magnetoencephalography.
  
  
  CONCLUSIONS
  The exact role of cortical excitability changes in migraine pathophysiology and possibly in chronic migraine is still unknown. Further studies are also necessary to clarify the role of migraine preventive drugs on brain excitability.
  
  
  CONCLUSIONS
  In this review, the results of neurophysiological studies conducted in migraine patients will be described and the associated pathophysiological hypotheses will be discussed.
authors.affiliation: Service de neurologie, hôpital de la Croix-Rousse, hospices civils de Lyon, 103, grande rue de la Croix-Rousse, 69004 Lyon, France. g.demarquay@wanadoo.fr
authors.forename: G
authors.initials: G
authors.lastname: Demarquay
authors.forename: N
authors.initials: N
authors.lastname: André-Obadia
authors.forename: A
authors.initials: A
authors.lastname: Caclin
authors.forename: D
authors.initials: D
authors.lastname: Morlet
authors.forename: F
authors.initials: F
authors.lastname: Mauguière
mesh_terms: D002540:Cerebral Cortex / Q000503:physiopathology*; D013181:Cortical Spreading Depression / Q000502:physiology; D003943:Diagnostic Techniques, Neurological; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D006801:Humans; D008881:Migraine Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods