Multimodal Magnetic Resonance Imaging To Explore The Pathological Mechanism Of Migraine

Migraine,a complex and disabling brain disorder,is characterized by recurrent attack of moderate-to-severe headache,and in combination with nausea,vomiting,and hypersensitivities to visual,olfactory,somatosensory,and auditory stimuli.Migraine has a high prevalence over the world,and suffers may experience considerable disability that seriously affects the quality of life.Considering the enormous socioeconomic burden that migraine may cause,the pathophysiological mechanism that underlies the disease remain not fully understood,which hinders effective treatments for the disease.Previous neuroimaging studies have explored the functional and structural changes of migraine patients usually from the perspective of the whole brain,reflecting the neuroimaging changes brought by this disorder.With advances in technology,we utilized multimode magnetic resonance imaging（MRI）to subtlely explore functional and structural changes in subregions of key brain in trigeminal pain pathways in migraine patients,and by using blood oxygen level-dependent（BOLD）signals to explore functional connectivity（FC）between white matter fiber tracts and gray matter regions,which further reflect functional changes in white matter.Multimodal MRI data were acquired from 50 migraine without aura（MWo A）and50 healthy Control（HC）,including resting state functional MRI data,high resolution T₁-weighted imaging,and diffusion tensor imaging（DTI）.In the current study,we explored the FC between subregions of the key brain regions in the trigeminal pain pathway,like brainstem,thalamus and sensorimotor cortex and the whole brain.We found the functional connectivity between posterior pons and superior parietal lobule,middle temporal gyrus,and middle frontal gyrus decreased compared with HC.Moreover,the regional homogeneity（Re Ho）in posterior pons was reduced compared with HC.Studies on the FC of the thalamic subregion showed that the FC between the anterior dorsal nucleus of the thalamus and the precuneus were significantly reduced in MWo A patients.Additionally,the FCs between the ventral posterior nucleus of the thalamus and the precuneus,the inferior parietal lobule,and the middle frontal gyrus were significantly reduced.Studies on FC of the sensorimotor subregions found that compared with HC,FCs between the sensorimotor subregions and the posterior parietal lobe,visual cortex,temporal lobe,cingulate gyrus,prefrontal lobe,precuneus,sensorimotor region and cerebellum were interrupted in MWo A patients.These altered functional connectivities between pain related brain regions might result in dysfunction in the multisensory integration,pain processing,spatial attention,cognitive assessment and pain regulation.Some studies shown that the key brain regions in the trigeminal vascular pathway were abnormal in functional connectivity with other brain regions associated with pain.These areas of the brain associated with pain are often called the"pain matrix,"Abnormal functional connections between the"pain matrix"may be related to functional and structural abnormalities in the white matter bundles that connect these brain regions.In our previous study,structural changes in white matter of the brain were analyzed using DTI whole-brain analysis,and no structural changes were detected.In this study,we utilized spatially unbiased infratentorial template（SUIT）to detect structural changes in the cerebellum and brainstem of MWo A patients,and found microstructure changes in the inferior cerebellar peduncle,suggesting that there were abnormalities in the sensorimotor information transmission and integration of MWo As from the medulla to the cerebellar level.We also found reduced gray matter volume and altered diffusion characteristic in the spinal trigeminal nucleus（Sp V）,which might result in Sp V abnormally transmit and regulate harmful information from the brain’s blood vessels and meninges.We utilized improved data analysis methods to calculate the functional connections between the white matter fiber tracts and gray matter regions in migraine patients,and found disrupted functional connections between the white matter fiber tracts and gray matter regions,reflecting the functional abnormalities of the white matter fiber tracts and gray matter regions.These results suggested that connectivity abnormalities and functional abnormalities in cortical regions may not be limited to gray matter regions and are associated with functional abnormalities in white matter fiber tracts.These findings provide new insights into the neural basis of migraine pathology and will benefit the diagnosis and treatment of this disorder.