Structural and functional abnormalities in migraine patients without aura

Migraine is a primary headache disorder characterized by recurrent attacks of throbbing pain associated with neurological, gastrointestinal and autonomic symptoms. Previous studies have detected structural deficits and functional impairments in migraine patients. However, researchers have failed to investigate the functional connectivity alterations of regions with structural deficits during the resting state. Twenty-one migraine patients without aura and 21 age- and gender-matched healthy controls participated in our study. Voxel-based morphometric (VBM) analysis and functional connectivity were employed to investigate the abnormal structural and resting-state properties, respectively, in migraine patients without aura. Relative to healthy comparison subjects, migraine patients showed significantly decreased gray matter volume in five brain regions: the left medial prefrontal cortex (MPFC), dorsal anterior cingulate cortex (dACC), right occipital lobe, cerebellum and brainstem. The gray matter volume of the dACC was correlated with the duration of disease in migraine patients, and thus we chose this region as the seeding area for resting-state analysis. We found that migraine patients showed increased functional connectivity between several regions and the left dACC, i.e. the bilateral middle temporal lobe, orbitofrontal cortex (OFC) and left dorsolateral prefrontal cortex (DLPFC). Furthermore, the functional connectivity between the dACC and two regions (i.e. DLPFC and OFC) was correlated with the duration of disease in migraine patients. We suggest that frequent nociceptive input has modified the structural and functional patterns of the frontal cortex, and these changes may explain the functional impairments in migraine patients.