Migraine triggers and habituation of visual evoked potentials

Background: Identifying specific subsets of patients within the clinical spectrum of migraine could help in personalizing migraine treatment. Profiling patients by combining clinical characteristics and neurophysiological biomarkers is largely unexplored. We studied the association between migraine attack triggers and habituation of visual evoked potentials. Methods: We personally interviewed 25 patients about their migraine triggers following a structured list, and measured the N1-P1 habituation slope over six blocks of 100 averaged pattern-reversal VEP afterwards. Results: The mean number of triggers per patient was 4.52 1.42. Habituation slopes differed significantly between subjects who reported stress as a migraine trigger (deficient VEP habituation) and subjects who did not (preserved VEP habituation). For the remaining categories, the mean amplitude slope was always positive, indicating deficient habituation, and was not significantly different between subgroups. Conclusions: Migraine patients not reporting perceived stress as a trigger for their attacks might constitute a distinct clinic-physiological subset within the migraine spectrum

Familial history of migraine influences habituation of visual evoked potentials

peer reviewedBackground: Lack of habituation of visual evoked potentials (VEP) is a common finding in migraine patients between attacks. Previous studies have suggested an electrophysiological familial aggregation pattern associated with migraine. The aim of this study was to evaluate the influence of a positive familial history of migraine on VEP amplitude and habituation. Methods: We recorded six blocks of 100 VEP during continuous pattern-reversal stimulation in 30 patients with migraine between attacks (MO) and in 30 healthy volunteers, of whom 15 had a first-degree relative suffering from migraine (HVm) and 15 had not (HV). Results: Both MO and HVm had a significant deficit of VEP habituation and similarly reduced N1-P1 first block amplitudes, compared to HV (habituation slope: MO ¼ 0.033, HVm ¼ 0.021, HV ¼ 0.025, HV vs. MO p ¼ 0.002, HV vs. HVm p ¼ 0.036; mean N1-P1 amplitude in the first block: MO ¼ 9.08 mV, HVm ¼ 9.29 mV, HV ¼ 12.19 mV. HV vs. MO p ¼ 0.041, HV vs. HVm p ¼ 0.076). The first block N1-P1 amplitude was negatively correlated with the habituation slope for both MO (r ¼ .44, p ¼ 0.015) and HVm (r ¼ .56, p ¼ 0.031) while no significant correlation was found in HV (r ¼ .17, p ¼ 0.53). There were no differences in VEP latencies between the groups. Conclusions: Our study suggests that lack of habituation of visual evoked potentials is probably a genetically determined endophenotypic trait that is associated with both migraine and migraine susceptibility. We hypothesize that genetic diversity of populations could account for some of the discrepancies between electrophysiological studies performed in migraine and for interindividual variations among the subgroups

In silico analysis of gene expression in V3a and the superior occipital gyrus: Relevance for migraine

Introduction: Visual manifestations are the most prominent non-painful features of migraine. During the last decades, visual area V3a has gathered attention of headache scientists because of its apparent implication on aura initiation, photophobia and cortical hyper-responsiveness related to visual motion perception. In this hypothesis-generating study, we performed an in silico analysis of gene expression in left V3a and the cerebral gyrus that harbours it (left superior occipital gyrus (lSOG)) searching for transcriptomic patterns that could be linked with migraine’s pathophysiology. Materials and methods: Neurotransmitter receptor gene expression levels in left V3a were extracted from validated brain mRNA expression models using a probabilistic volumetric mask of this region. The primary visual cortex and other sensory cortices (auditory, olfactory and somatosensory) were used as comparators. Genome-wide transcriptomic differences between the gyrus harbouring left V3a (lSOG) and the rest of the cerebral cortex were assessed using the Allen Brain Institute Human RNA micro array atlas/database. Results: Adrenergic receptor β1, dopaminergic receptor D3 and serotoninergic receptors 1B, 1F and 2A, which have been previously implicated in migraine’s pathophysiology and/or treatment, showed significantly higher expression levels on left V3a. Transcriptomic differences between the lSOG harbouring V3a and the rest of the cortex comprise genes whose products are involved in neuronal excitability (SLC17A6, KCNS1, KCNG1 and GABRQ), activation of multiple signal transduction pathways (MET) and cell metabolism (SPHKAP via its interaction with cAMP-dependent protein kinase). Conclusions: Focal gene expression analysis of V3a suggests some clues about its implication in migraine. Further studies are warranted