BRAIN POTENTIAL DIFFERENCES RELATED TO SPATIAL ATTENTION IN MIGRAINEURS WITH AND WITHOUT AURA SYMPTOMS SUPPORT SUPPOSED DIFFERENCES IN ACTIVATION

It is to be expected that differences in electrical activity of the br ain between migraine patients with aura and those without aura can onl y be revealed by stimuli that provoke visual spatial processing, i.e. stimuli that trigger so called endogenous Visual Evoked Potential (VEP ) activity. This is not the case for the flashes and checkerboard reve rsals. Those stimuli elicited exogenous activity only. During and betw een attacks the blood flow of migraineurs with aura changes in the pos terior cerebral part of the brain, which is assumed to be specialized in the processing of spatial aspects of visual stimuli. Reaction times (RTs), early and late Event Related Potential (ERP) differences were compared at 12 scalp positions for two groups of migraineurs (with and without aura) and a control group. They had to perform a passive afte ntion task, checkerboard reversals, and an active attention task, wher e attention was either divided into or focussed at spatial locations. In agreement with many studies on migraine, checkerboard stimuli did n ot differ on any early components. However, RTs were faster for migrai neurs with aura and their early components were different when stimuli were highly attended. This is probably because these stimuli can rela tively easily trigger cortical activity due to an over activated centr al mechanism and an enhanced level of attention.