Thickening in the somatosensory cortex of patients with migraine

Application of the Migraine Aura Complexity Score (MACS): Clinical and Neuroimaging Study

Background: Manifestations of typical migraine aura can be numerous. Investigation of its pathophysiological mechanisms can be challenging if a stratification of phenotypes is not performed. In this context, the Migraine Aura Complexity Score (MACS), recently developed, may help. Here we aimed to categorize migraine patients into homogenous groups using MACS and to compare those groups with respect to patients' characteristics and neuroimaging findings. Methods: Participants who have a migraine with aura (MwA) were interviewed after each attack in order to obtain the characteristics of migraine aura. Thereafter, we scored the complexity of their auras by MACS. The MACS was used to categorize patients into three groups: MwA-S (with simple aura), MwA-MC (with moderately complex aura), and MwA-C (with complex aura). The patient characteristics and estimated cortical thickness of regions of interest, which are potentially linked to the symptoms that develop during the aura, were used to compare these groups. Results: In total, 338 MwA attacks were recorded in analyzed groups. Scotoma was the most frequently reported symptom in the groups, followed by somatosensory aura in the MwA-C group and zig-zag lines in the MwA-MC and MwA-S groups. Patients in the MwA-C and MwA-MC groups had a thicker cortex in the left primary visual cortex with respect to MwA-S group. In addition, patients in the MwA-C group had a thicker cortex in several visual and somatosensory cortical regions relative to the MwA-S group. Conclusions: Our results show that the newly developed MACS can be used for the stratification of MwA patients, herewith allowing the better investigation of changes in migraineurs' brains.

Transient Neurologic Dysfunction in Migraine

Transient disturbances in neurologic function are disturbing features of migraine attacks. Aura types include binocular visual, hemi-sensory, language and unilateral motor symptoms. Because of the gradual spreading quality of visual and sensory symptoms, they were thought to arise from the cerebral cortex. Motor symptoms previously included as a type of migraine aura were reclassified as a component of hemiplegic migraine. ICHD-3 criteria of the International Headache Society, added brainstem aura and retinal aura as separate subtypes. The susceptibility to all types of aura is likely to be included by complex and perhaps epigenetic factors.

Shedding light on migraine with aura: the clarifying role of advanced neuroimaging investigations

Introduction: While migraine with aura is a complex neurological syndrome with a well-characterized clinical phenotype, its pathophysiology still has grey areas which could be partially clarified by microstructural and functional neuroimaging investigations. Areas covered: This article, summarizing the most significant findings from advanced neuroimaging studies, aims to achieve a unifying pathophysiological model of the migraine aura. A comprehensive review has been conducted of PubMed citations by entering the key word 'neuroimaging' combined with 'migraine with aura' AND/OR 'MRI.' Other keywords included 'grey matter' OR 'white matter', 'structural' OR 'functional'. Expert opinion: Converging evidence from advanced neuroimaging investigations underlined the critical role of the extrastriate visual cortex, and in particular the lingual gyrus, in the genesis of the aura phenomenon. However, the relationship between the aura and the headache phase of migraine attacks has not been completely clarified, to date, and underlying pathophysiological mechanisms need to be further elucidated.

Positron emission tomography imaging of endogenous mu-opioid mechanisms during pain and migraine

The enormous advancements in the medical imaging methods witnessed in the past decades have allowed clinical researchers to study the function of the human brain in vivo, both in health and disease. In addition, a better understanding of brain responses to different modalities of stimuli such as pain, reward, or the administration of active or placebo interventions has been achieved through neuroimaging methods. Although magnetic resonance imaging has provided important information regarding structural, hemodynamic, and metabolic changes in the central nervous system related to pain, magnetic resonance imaging does not address modulatory pain systems at the molecular level (eg, endogenous opioid). Such important information has been obtained through positron emission tomography, bringing insights into the neuroplastic changes that occur in the context of the pain experience. Positron emission tomography studies have not only confirmed the brain structures involved in pain processing and modulation but also have helped elucidate the neural mechanisms that underlie healthy and pathological pain regulation. These data have shown some of the biological basis of the interindividual variability in pain perception and regulation. In addition, they provide crucial information to the mechanisms that drive placebo and nocebo effects, as well as represent an important source of variability in clinical trials. Positron emission tomography studies have also permitted exploration of the dynamic interaction between behavior and genetic factors and between different pain modulatory systems. This narrative review will present a summary of the main findings of the positron emission tomography studies that evaluated the functioning of the opioidergic system in the context of pain.

Structural and Functional Reorganization of the Brain in Migraine Without Aura

It remains unknown whether migraine headache has a progressive component in its pathophysiology. Quantitative MRI may provide valuable insight into abnormal changes in the migraine interictum and assist in identifying disrupted brain networks. We carried out a data-driven study of structural integrity and functional connectivity of the resting brain in migraine without aura. MRI scanning was performed in 36 patients suffering from episodic migraine without aura and 33 age-matched healthy subjects. Voxel-wise analysis of regional brain volume was performed by registration of the T1-weighted MRI scans into a common study brain template using the tensor-based morphometry (TBM) method. Changes in functional synchronicity of the brain networks were assessed using probabilistic independent component analysis (ICA). TBM revealed that migraine is associated with reduced volume of the medial prefrontal cortex (mPFC). Among 375 functional brain networks, resting-state connectivity was decreased between two components spanning the visual cortex, posterior insula, and parietal somatosensory cortex. Our study reveals structural and functional alterations of the brain in the migraine interictum that may stem from underlying disease risk factors and the "silent" aura phenomenon. Longitudinal studies will be needed to investigate whether interictal brain changes are progressive and associated with clinical disease trajectories.

Primary headaches during lifespan

Primary headaches are one of the most prevalent neurological disorders and can occur during a wide range of lifespan. Primary headaches, especially migraine, are cyclic disorders with a complex sequence of symptoms within every headache attack. There is no systematic review of whether these symptoms changes during lifespan. Indeed, the clinical presentation of migraine shows an age-dependent change with a significantly shorter duration of the attacks and occurrence of different paroxysmal symptoms, such as vomiting, abdominal pain or vertigo, in childhood and, in contrast, largely an absence of autonomic signs and a more often bilateral headache in the elderly. The age-dependent differences in the clinical presentation are less distinct in cluster headache and, especially, in tension-type headache. The differences in the clinical presentation are in agreement with the idea that the connectivity of hypothalamic areas with different brainstem areas, especially the central parasympathetic areas, is important for the clinical manifestation of migraine, as well as, the change during lifespan.

Neuroimaging clues of migraine aura

While migraine headaches can be provoked, or predicted by the presence of an aura or premonitory symptoms, the prediction or elicitation of the aura itself is more problematic. Therefore, imaging studies directly examining the aura phenomenon are sparse. There are however interictal imaging studies that can shed light on the pathophysiology of the migraine with aura (MWA) cascade. Here, we review findings pointing to the involvement of cortical spreading depression (CSD) and neuroinflammation in MWA. Whether asymptomatic CSD also happens in some migraine without aura is still under debate. In addition, new evidence points to glial activation in MWA, indicating the involvement of astrocytes in the neuroinflammatory cascade that follows CSD, as well as dural macrophages, supporting the involvement of the trigeminovascular system in migraine pain.

Altered neural activity to monetary reward/loss processing in episodic migraine

The dysfunctions of the mesolimbic cortical reward circuit have been proposed to contribute to migraine pain. Although supporting empirical evidence was mainly found in connection with primary rewards or in chronic migraine where the pain experience is (almost) constant. Our goal however was to investigate the neural correlates of secondary reward/loss anticipation and consumption using the monetary incentive delay task in 29 episodic migraine patients and 41 headache-free controls. Migraine patients showed decreased activation in one cluster covering the right inferior frontal gyrus during reward consumption compared to controls. We also found significant negative correlation between the time of the last migraine attack before the scan and activation of the parahippocampal gyrus and the right hippocampus yielded to loss anticipation. During reward/loss consumption, a relative increase in the activity of the visual areas was observed the more time passed between the last attack and the scan session. Our results suggest intact reward/loss anticipation but altered reward consumption in migraine, indicating a decreased reactivity to monetary rewards. The findings also raise the possibility that neural responses to loss anticipation and reward/loss consumption could be altered by the proximity of the last migraine attack not just during pre-ictal periods, but interictally as well.

Volume alterations of brainstem subregions in migraine with aura

Background

The brainstem plays a significant role in migraine pathogenesis, but a relationship between volume alterations of brainstem subregions and migraine aura characteristics has not been sufficiently investigated. The aim of this study is to compare the volume of the brainstem, and its subregions, between patients with a migraine with aura (MwA) and healthy controls (HC), and also to correlate characteristics of MwA and the volume of the brainstem subregions.

Methods

Forty-two MwA and 42 HCs, balanced by sex and age, were selected for this study. Total brainstem volume changes as well as volume changes in the pons, medulla, midbrain and the superior cerebellar peduncles were investigated in MwA relative to HCs. In addition, the relationships between brainstem subregions and aura characteristics (aura duration, the frequency of the aura, occurrence of somatosensory and dysphasic aura, duration of a headache, intensity of headache pain and disease duration) were explored in MwA.

Results

MwA patients had a larger brainstem volume relative to HCs (25,941.35 ± 2559.2 mm³ vs. 25,179.32 ± 2019.1 mm³; p = .008), as well as the midbrain and pons (6155.98 ± 565.7 mm³ vs. 5964.22 ± 457.0 mm³, p = .002; 15,105.13 ± 1765.5 mm³ vs. 14,539.89 ± 1408.4 mm³, p = .007, respectively). Total brainstem volume, as well as volumes of brainstem subregions, were not significantly correlated to the MwA characteristics.

Conclusion

The results of this study reveal that a migraine with aura is associated with a larger volume of the brainstem with a particular involvement of the midbrain and pons.

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Migraineurs with aura had larger volume of pons and midbrain relative to controls.

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Medulla did not significantly differ in volume size between migraineurs and controls.

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Volume of brainstem is not linked to disease duration and intensity of headache pain.

Subcortical Volume Changes in Migraine with Aura

Background and Purpose

Various features of the cerebral cortex and white matter have been extensively investigated in migraine with aura (MwA), but the morphological characteristics of subcortical structures have been largely neglected. The aim of this study was to identify possible differences in subcortical structures between MwA patients and healthy subjects (HS), and also to determine the correlations between the characteristics of migraine aura and the volumes of subcortical structures.

Methods

Thirty-two MwA patients and 32 HS matched by sex and age were analyzed in this study. Regional subcortical brain volumes were automatically calculated using the FSL/FMRIB Image Registration and Segmentation Tool software (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Glossary). A general linear model analysis was used to investigate differences in the volume of subcortical structures between the MwA patients and HS. A partial correlation test was used to assess correlations between the volume of subcortical structures and characteristics of MwA.

Results

The volumes of the right globus pallidus, left globus pallidus, and left putamen were significantly smaller in MwA patients than in HS (mean±SD): 1,427±135 mm³ vs. 1,557±136 mm³ (p<0.001), 1,436±126 mm³ vs. 1,550±139 mm³ (p=0.001), and 4,235±437 mm³ vs. 4,522±412 mm³ (p=0.006), respectively. There were no significant relationships between subcortical structures and clinical parameters.

Conclusions

These findings suggest that both the globus pallidi and left putamen play significant roles in the pathophysiology of the MwA. Future studies should determine the cause-and-effect relationships, since these could not be discriminated in this study due to its cross-sectional design.

Cortical abnormalities in episodic migraine: A multi-center 3T MRI study

BACKGROUND

Several previous studies have investigated cortical abnormalities, specifically cortical thickness, in patients with migraine, with variable results. The relatively small sample sizes of most previous studies may partially explain these inconsistencies.

OBJECTIVE

To investigate differences of cortical thickness between control subjects and migraineurs in a large cohort.

METHODS

Three Tesla MRI data of 131 patients (38 with and 93 without aura) and 115 control subjects were analysed. A vertex-wise linear model was applied controlling for age, gender and MRI scanner to investigate differences between groups and determine the impact of clinical factors on cortical thickness measures.

RESULTS

Migraineurs showed areas of thinned cortex compared with controls bilaterally in the central sulcus, in the left middle-frontal gyrus, in left visual cortices and the right occipito-temporal gyrus. Frequency of migraine attacks and the duration of the disorder had a significant impact on cortical thickness in the sensorimotor cortex and middle-frontal gyrus. Patients without aura showed thinner cortex than controls bilaterally in the central sulcus and in the middle frontal gyrus, in the left primary visual cortices, in the left supramarginal gyrus and in the right cuneus. Patients with aura showed clusters of thinner cortex bilaterally in the subparietal sulcus (between the precuneus and posterior cingulate cortex), in the left intraparietal sulcus and in the right anterior cingulate.

CONCLUSION

These results indicate cortical abnormalities in specific brain regions in migraineurs. Some of the observed abnormalities may reflect a genetic susceptibility towards developing migraine attacks, while others are probably a consequence of repeated head pain attacks.

Transcranial direct current stimulation to prevent and treat surgery-induced opioid dependence: a systematic review

Opioid misuse leading to dependence is a major health issue. Recent studies explored valid alternatives to treat pain in postsurgical settings. This systematic review aims to discuss the role of transcranial direct current stimulation (tDCS) in preventing and treating postoperative pain and opioid dependence. PubMed and Embase databases were screened, considering studies testing tDCS effects on pain and opioid consumption in surgical settings and opioid addiction. Eight studies met our inclusion criteria. Results showed a reduction of postoperative pain, opioid consumption and cue-induced craving following cortical stimulation. Despite the limited number of studies, this review shows preliminary encouraging evidence regarding the analgesic role of tDCS. However, future studies are needed to further investigate the application of tDCS in postsurgical settings.

Proposal for a Migraine Aura Complexity Score

Objectives

Currently, there is no scoring system for assessing the complexity of migraine aura. Our goal was to develop a Migraine Aura Complexity Score that synthesizes the quantity and quality of aura symptoms and to test its applicability in neuroimaging studies.

Methods

Patients with migraine aura were interviewed in order to obtain characteristics of migraine aura. Explorative and confirmatory analyses were used to develop the Migraine Aura Complexity Score. Median values were derived from 10 consecutive migraine auras in each patient. The Migraine Aura Complexity Score was correlated with an average cortical thickness of different brain areas in studied patients. The Surface-based Morphometric Analysis approach was used to estimate cortical thickness.

Results

This study included 23 (16 females and seven males) migraineurs with aura. Confirmatory factor analysis suggested the second-order model with three-factor measurement for grading migraine aura. The first factor is linked to higher cortical dysfunction during migraine aura, while the second is associated with the degree of involvement of primary visual and somatosensory cortices; the third linked symptoms of somatosensory aura and hand and head involvement. Positive correlation of Migraine Aura Complexity Score and averaged cortical thickness were found in the left and right hemispheres overall (r = 0.568, p = 0.007; r = 0.617, p = 0.003) and in some of their regions.

Conclusions

This study demonstrates that the Migraine Aura Complexity Score could be a valuable tool for assessing migraine aura. The score could be used in neuroradiological studies in order to achieve a stratification of patients with migraine aura.

Patterns of gray matter alterations in migraine and restless legs syndrome

Objectives

Migraine and restless legs syndrome (RLS) are often comorbid and share elements of pathology; however, their neuroanatomical underpinnings are poorly understood. This study aimed to identify patterns of gray matter volume (GMV) alteration specific to and common among patients with RLS, migraine, and comorbid migraine and RLS.

Methods

High‐resolution T1‐weighted images were acquired from 116 subjects: 27 RLS patients, 22 migraine patients, 22 patients with comorbid migraine and RLS, and 45 healthy controls. Direct group comparisons and conjunction analysis were first used to localize the distinct and shared neural signatures of migraine and RLS. We also investigated whether the shared neural signature could be replicated in an additional comorbid migraine/RLS group.

Results

Compared with healthy controls, migraine patients showed GMV changes in the lateral occipital cortex, cerebellum, frontal pole, and middle frontal gyrus (MFG), and RLS patients showed GMV changes in the thalamus, middle temporal gyrus, anterior cingulate cortex, insular cortex, and MFG. In migraine, compared with RLS, GMV differences were found in the precuneus, lateral occipital and occipital fusiform cortex, superior frontal and precentral gyri, and cerebellum. Conjunction analyses for these disorders showed altered GMV in the MFG, also found in patients with comorbid migraine and RLS. The GMV of the MFG also correlated with sleep quality in patients with comorbid migraine and RLS.

Interpretation

Migraine and RLS are characterized by shared and distinctive neuroanatomical characteristics, with a specific role of the MFG. These findings may be related to shared pathophysiology of these two distinct disorders.

Reduced cortical thickness in Heschl's gyrus as an in vivo marker for human primary auditory cortex

The primary auditory cortex (PAC) is located in the region of Heschl's gyrus (HG), as confirmed by histological, cytoarchitectonical, and neurofunctional studies. Applying cortical thickness (CTH) analysis based on high-resolution magnetic resonance imaging (MRI) and magnetoencephalography (MEG) in 60 primary school children and 60 adults, we investigated the CTH distribution of left and right auditory cortex (AC) and primary auditory source activity at the group and individual level. Both groups showed contoured regions of reduced auditory cortex (redAC) along the mediolateral extension of HG, illustrating large inter-individual variability with respect to shape, localization, and lateralization. In the right hemisphere, redAC localized more within the medial portion of HG, extending typically across HG duplications. In the left hemisphere, redAC was distributed significantly more laterally, reaching toward the anterolateral portion of HG. In both hemispheres, redAC was found to be significantly thinner (mean CTH of 2.34 mm) as compared to surrounding areas (2.99 mm). This effect was more dominant in the right hemisphere rather than in the left one. Moreover, localization of the primary component of auditory evoked activity (P1), as measured by MEG in response to complex harmonic sounds, strictly co-localized with redAC. This structure-function link was found consistently at the group and individual level, suggesting PAC to be represented by areas of reduced cortex in HG. Thus, we propose reduced CTH as an in vivo marker for identifying shape and localization of PAC in the individual brain.

Morphometric changes over the whole brain in caffeine-containing combination-analgesic-overuse headache

Objective

To investigate brain morphometric changes in medication-overuse headache with excessive intake of caffeine-containing combination analgesics.

Materials and methods

We recruited 32 medication-overuse headache patients overusing caffeine-containing combination analgesics and 26 normal controls with matched sex and age. Magnetic resonance T1-weighted images were processed by automatic volume algorithm of brain regions over the whole brain according to the neuromorphometrics template. We explored the volume differences between groups and correlation with clinical variables.

Results

Medication-overuse headache patients demonstrated decreased volume in cerebellum, optic chiasm, and increased volume in right lateral orbital gyrus, left calcarine, bilateral middle occipital gyrus, right superior parietal lobe, and right temporal transverse gyrus compared with normal controls. The increased volume was primarily contributed by patients of lower headache frequency (10–20 days/month) and with no psychological comorbidities. In regression analyses, the volume of bilateral middle occipital gyrus had negative association with migraine duration, and the volume of right lateral orbital gyrus and right superior parietal lobe was negatively correlated with number of medications per month.

Conclusions

Volume changes of brain regions involved in affective and cognitive processing, visual and auditory perception, and pain sensory/discrimination suggested a particular role of those regions in the pathogenesis of medication-overuse headache overusing caffeine-containing combination analgesics. Morphometric changes in multiple visual processing areas and volume gain in lower headache frequency and less anxiety and depression may be specific features related to overusing caffeine-containing combination analgesics.

Migraine and cluster headache - the common link

Although clinically distinguishable, migraine and cluster headache share prominent features such as unilateral pain, common pharmacological triggers such glyceryl trinitrate, histamine, calcitonin gene-related peptide (CGRP) and response to triptans and neuromodulation. Recent data also suggest efficacy of anti CGRP monoclonal antibodies in both migraine and cluster headache. While exact mechanisms behind both disorders remain to be fully understood, the trigeminovascular system represents one possible common pathophysiological pathway and network of both disorders. Here, we review past and current literature shedding light on similarities and differences in phenotype, heritability, pathophysiology, imaging findings and treatment options of migraine and cluster headache. A continued focus on their shared pathophysiological pathways may be important in paving future treatment avenues that could benefit both migraine and cluster headache patients.

Migraine improvement correlates with posterior cingulate cortical thickness reduction

Objective The main goal of this study was to correlate migraine improvement, after prophylactic therapy, with cortical thickness changes. Methods Cortical thickness maps were obtained with magnetic resonance imaging (MRI) from 19 patients with migraine before (first scan) and after (second scan) prophylactic treatment, and these were compared with controls using the FreeSurfer MRI tool. Cortical changes were correlated with the headache index (HI). Results Anincrease incortical thickness was found in the right cuneus and precuneus, somatosensory and superior parietal cortices in both patient scans, compared with the controls. No changes were observed in the left hemisphere. Following correction for multiple comparisons, no areas changed from the first to the second scan. Regression analysis showed a significant negative correlation between the HI improvement and cortical thickness changes in the left posterior cingulate, a region involved with nociception and, possibly, the development of chronic pain. Conclusion There were changes in cortical thickness in patients with migraine relative to controls in areas involved with vision and pain processing. Left posterior cingulate cortical changes correlated with headache frequency and intensity.

Microstructural changes in the brain in elderly patients with irritable bowel syndrome

OBJECTIVE

It is unclear how alterations in gray matter volume and white matter density affect elderly patients with irritable bowel syndrome (IBS). This study aimed to investigate the relationship between structural changes in the brain and psychological stress in elderly IBS patients.

METHODS

Eighteen IBS patients and 12 healthy controls underwent structural magnetic resonance imaging. Voxel-based morphometry and diffusion tensor imaging analysis were used to identify abnormalities in cortical regions and white matter, respectively.

RESULTS

The IBS group showed a significant GMV reduction in the cingulate gyrus, occipital lobe, hippocampus, frontal lobe, medial frontal gyrus, superior frontal gyrus, and limbic lobe as well as a higher GMV in the insula, superior temporal gyrus, angular gyrus, and supramarginal gyrus. Diffusion tensor imaging indicated that the IBS group had lower fractional anisotropy in the corpus callosum, upper corona, fornix, internal capsule, and brainstem. Additionally, IBS patients showed higher mean diffusivity in the cingulate gyrus, corpus callosum, upper corona, internal capsule, external capsule, fornix, and superior longitudinal fasciculus.

CONCLUSION

Structural changes in the brain play a role in the condition of elderly IBS patients. Psychological stress is an important factor for developing IBS via the hypothalamic-pituitary-adrenal axis.

Advances in migraine neuroimaging and clinical utility: from the MRI to the bedside

INTRODUCTION

In current migraine clinical practice, no specific diagnostic investigations are available and therefore the diagnosis is an eminently clinical process where instrumental examinations may have a part to exclude possible causes of secondary headaches. While migraine clinical phenotype has been widely characterized, migraine pathophysiology has still a gap that might be partly bridged by structural and functional neuroimaging investigations. Areas covered: This article aims to review the recent advances in functional neuroimaging, the consequent progress in the knowledge of migraine pathophysiology and their putative application and impact in the clinical setting. A comprehensive review was conducted of PubMed citations by entering the key word 'MRI' combined with 'migraine' AND/OR 'headache.' Other key words included 'gray matter' OR 'white matter,' 'structural' OR 'functional.' The only restriction was English-language publication. The abstracts of all articles meeting these criteria were reviewed, and full texts were examined for relevant references. Expert commentary: Advanced magnetic resonance imaging (MRI) techniques are tremendously improving our knowledge about brain abnormalities in migraine patients. However, advanced MRI could nowadays overcome the limits linked to the clinicians' judgment through the identification of objectively measurable neuroimaging findings (quantitative biomarkers) concerning the diagnosis, the prognosis and 'tailored' therapeutic-care pathways.

Gray matter volume modifications in migraine

Objective

To explore cross-sectional and longitudinal gray matter (GM) volume changes in patients with migraine and their association with patients' clinical characteristics and disease activity.

Methods

Brain T2-weighted and 3-dimensional T1-weighted scans were acquired from 73 episodic migraineurs and 46 age- and sex-matched nonmigraine controls at baseline. Twenty-four migraineurs and 25 controls agreed to be reexamined after a mean follow-up of 4 years. Using a general linear model and SPM12, a whole-brain analysis was performed to assess GM volume modifications.

Results

At baseline, compared to controls, patients with migraine showed lower cerebellar GM volume and higher volume of regions of the frontotemporal lobes. At follow-up, migraineurs were significantly older than controls. Over the follow-up, migraineurs developed an increased volume of frontotemporoparietal regions, which was more prominent in patients with a higher baseline disease activity: long disease duration and high attack frequency. Migraineurs also developed decreased GM volume of visual areas, which was related to higher pain severity. Patients with an increased attack frequency at follow-up experienced both increased and decreased volume of nociceptive regions. In migraineurs, reduced GM volume of extrastriate visual areas during the follow-up was significantly correlated to baseline disease activity: shorter disease duration and lower attack frequency.

Conclusion

In this cohort, the migraine brain changes dynamically over time, and different pathophysiologic mechanisms can occur in response to patients' disease severity. The interaction between predisposing brain traits and experience-dependent responses might vary across different nociceptive and visual areas, thus leading to distinct patterns of longitudinal GM volume changes.

Migraine with Aura: Surface-Based Analysis of the Cerebral Cortex with Magnetic Resonance Imaging

Objective

Previous migraine studies have reported gray matter alterations in various cortical regions with conflicting results. This study aimed to explore a cortical morphometric difference in migraineurs with aura (MA) compared to healthy subjects (HS) and to delineate a possible difference between the cortical morphological features and different aura phenotypes.

Materials and Methods

Forty-eight MA and 30 HS that were balanced by sex, age, and educational level were selected for this study. T2-weighted and three-dimensional T1-weighted magnetic resonance imaging (MRI) of the brain were acquired using a 1.5T MRI scanner. Surface-based morphometry from the MRI data was used to identify differences between the MA and HS group, and then between MA subgroups. The MA group was subdivided into migraineurs who experienced only visual aura (MVA) and migraineurs who had visual, somatosensory and dysphasic symptoms (MVA+).

Results

The MVA+ group had significantly reduced cortical surface area of the left rostral middle frontal cortex compared with the MVA group (p < 0.001). Migraine patients had significantly reduced volume of the left fusiform gyrus relative to HS (p < 0.001). Also, the sulcal depth increased at the level of the left temporal pole in the MVA+ group relative to the MVA group (p < 0.001). The vertex-by-vertex analysis did not exhibit any significant difference in cortical thickness between MA and HS, and between MVA+ and MVA, when corrected for multiple comparisons.

Conclusion

Migraineurs with aura demonstrates different morphometric features from HS in multiple cortical regions. MVA+ have different morphometric features in the left frontal and temporal lobe relative to MVA, which could be a source of distinct symptoms and serve as potential biomarkers of different MA subtypes.

Functional Neuroimaging Biomarkers in Migraine: Diagnostic, Prognostic and Therapeutic Implications

BACKGROUND

In current migraine clinical practice, conventional neuroimaging examinations are often sought to exclude possible causes of secondary headaches or migraineassociated disorders. Contrariwise, although advanced Magnetic Resonance Imaging (MRI) has improved tremendously our understanding of human brain processes in migraine patients, to the state of the art they have not superseded the conventional neuroimaging techniques in the migraine clinical setting.

METHODS

A comprehensive review was conducted of PubMed citations by entering the keyword "marker" and/or "biomarker" combined with "migraine" and/or "headache". Other keywords included "imaging" or "neuroimaging", "structural" or "functional". The only restriction was English-language publication. The abstracts of all articles meeting these criteria were reviewed, and the full text was retrieved and examined for relevant references.

RESULTS

Several authors tried to identify imaging biomarkers able to identify different migraine phenotypes or, even better, to follow-up the same migraine patients during the course of the disease, to predict the evolution into more severe phenotypes and, finally, the response to specific treatment.

CONCLUSION

The identification of diagnostic, prognostic and therapeutic advanced neuroimaging biomarkers in the migraine clinical setting, in order to approach to patients in a more and more rational and "tailored" way, is extremely intriguing and futuristic. Unfortunately, reliable and robust neuroimaging biomarkers are still lacking for migraine, probably due to both not completely understood pathogenesis and clinical and neuroimaging heterogeneity. Although further longitudinal advanced neuroimaging studies, aimed to identify effective neuroimaging biomarkers, are needed, this review aims to collect the main and most recent works on this topic.

Definition of Balance and Cognition Related to Disability Levels in Vestibular Migraine Patients

Objective

To compare the balance and cognition of vestibular migraine (VM) patients with migraineurs without vertigo history and healthy subjects, and to examine the effects of disability level on these functions.

Material-method

The study consisted of 32 VM patients, 32 migraineurs and 31 healthy subjects with similar sex and age. Balance functions were assessed with Balance Evaluation Systems Test (BEST), dizziness and headache severity with Visual Analogue Scale (VAS), disability related to dizziness with Dizziness Handicap Inventory (DHI), cognition with Stroop test.

Results

There was no statistical significant difference among the three groups in terms of age, gender, height, weight, marital status and education levels (p>0.05). Headache severity was higher in migraineurs than vestibular migraineurs and healthy subjects, also dizziness severity was higher in vestibular migraineurs than migraineurs and healthy subjects (p<0.0167). The outcomes of BEST 4, 5, 6 and BEST-total were significantly impaired in VM patients than migraineurs and healthy subjects, and worse in migraineurs rather than healthy subjects (p<0.0167). Stroop effect of cognitive examination was worse in VM and migraine patients rather than healthy subjects (p<0.0167). There was no significantly difference between VM and migraineurs (p>0.0167). There was a negative correlation between Stroop effect and BEST-total in VM patients significantly (r=-0.509, p=0.003), and no significant correlation in migraineurs (p>0.05). Disability levels of VM patients were low in 38.7%, mild in 51.6% and severe in 9.7% related to DHI. There was no significant difference between balance and cognition function in terms of disability levels (p>0.05).

Conclusion

The balance and cognition in VM patients and migraineurs were impaired rather than healthy subjects. The patient groups differed from each other in terms of vertiginous complaints rather than cognition. Solving the functional limitations with further longitudinal examinations can facilitate the treatment. The appropriate physiotherapy programs and patient education methods can be planned for these various issues.

Reward Circuitry Plasticity in Pain Perception and Modulation

Although pain is a widely known phenomenon and an important clinical symptom that occurs in numerous diseases, its mechanisms are still barely understood. Owing to the scarce information concerning its pathophysiology, particularly what is involved in the transition from an acute state to a chronic condition, pain treatment is frequently unsatisfactory, therefore contributing to the amplification of the chronic pain burden. In fact, pain is an extremely complex experience that demands the recruitment of an intricate set of central nervous system components. This includes cortical and subcortical areas involved in interpretation of the general characteristics of noxious stimuli. It also comprises neural circuits that process the motivational-affective dimension of pain. Hence, the reward circuitry represents a vital element for pain experience and modulation. This review article focuses on the interpretation of the extensive data available connecting the major components of the reward circuitry to pain suffering, including the nucleus accumbens, ventral tegmental area, and the medial prefrontal cortex; with especial attention dedicated to the evaluation of neuroplastic changes affecting these structures found in chronic pain syndromes, such as migraine, trigeminal neuropathic pain, chronic back pain, and fibromyalgia.

Volumetric brain changes in migraineurs from the general population

OBJECTIVE

To assess volumetric brain changes in migraineurs from the general population compared with controls.

METHODS

Structural brain changes in migraineurs from the general population-based MRI Cerebral Abnormalities in Migraine, an Epidemiologic Risk Analysis (CAMERA)-2 observational cohort study were assessed by state-of-the-art voxel-based morphometry. T1-weighted MRIs of 84 migraineurs (52 with aura, 32 without aura) and 35 headache-free controls were evaluated. Regional volumes were compared voxelwise, corrected for age, sex, and total intracranial volume, with region-of-interest and whole-brain analyses.

RESULTS

In region-of-interest analyses, migraineurs showed decreased gray matter volume in the visual areas V3 and V5 of the right occipital cortex compared to controls (p < 0.05, familywise error correction). Post hoc analyses revealed that similar changes were present regardless of migraine aura status, disease activity (>1 year attack-free [inactive] vs ≥1 attack within the last year [active] and attack frequency [≤1 (low) vs ≥1 attack per month [high]). In exploratory whole-brain analyses (p < 0.001, uncorrected for multiple comparisons), we identified additional structural differences in migraineurs in other cortical and subcortical areas, including white matter tracts, that are particularly involved in visual processing.

CONCLUSIONS

Migraineurs from the general population showed small volumetric brain changes, mainly in cortical areas involved in visual motion processing, compared to controls. The presence of morphologic changes regardless of the presence of migraine aura or disease activity suggests that migraines with and without aura share common pathophysiologic pathways and suggests that these changes are (partially) irreversible or might have been present throughout life.

Cyclic Vomiting Syndrome is characterized by altered functional brain connectivity of the insular cortex: A cross-comparison with migraine and healthy adults

Cyclic Vomiting Syndrome (CVS) has been linked to episodic migraine, yet little is known about the precise brain-based mechanisms underpinning CVS, and whether these associated conditions share similar pathophysiology. We investigated the functional integrity of salience (SLN) and sensorimotor (SMN) intrinsic connectivity networks in CVS, migraine and healthy controls using brain functional Magnetic Resonance Imaging. CVS, relative to both migraine and controls, showed increased SLN connectivity to middle/posterior insula, a key brain region for nausea and viscerosensory processing. In contrast, this same region showed diminished SMN connectivity in both CVS and migraine. These results highlight both unique and potentially shared pathophysiology between these conditions, and suggest a potential target for therapeutics in future studies.

In child and adult migraineurs the somatosensory cortex stands out … again: An arterial spin labeling investigation

Over the past decade, human brain imaging investigations have reported altered regional cerebral blood flow (rCBF) in the interictal phase of migraine. However, there have been conflicting findings across different investigations, making the use of perfusion imaging in migraine pathophysiology more difficult to define. These inconsistencies may reflect technical constraints with traditional perfusion imaging methods such as single-photon emission computed tomography and positron emission tomography. Comparatively, pseudocontinuous arterial spin labeling (pCASL) is a recently developed magnetic resonance imaging technique that is noninvasive and offers superior spatial resolution and increased sensitivity. Using pCASL, we have previously shown increased rCBF within the primary somatosensory cortex (S1) in adult migraineurs, where blood flow was positively associated with migraine frequency. Whether these observations are present in pediatric and young adult populations remains unknown. This is an important question given the age-related variants of migraine prevalence, symptomology, and treatments. In this investigation, we used pCASL to quantitatively compare and contrast blood flow within S1 in pediatric and young adult migraineurs as compared with healthy controls. In migraine patients, we found significant resting rCBF increases within bilateral S1 as compared with healthy controls. Furthermore, within the right S1, we report a positive correlation between blood flow value with migraine attack frequency and cutaneous allodynia symptom profile. Our results reveal that pediatric and young adult migraineurs exhibit analogous rCBF changes with adult migraineurs, further supporting the possibility that these alterations within S1 are a consequence of repeated migraine attacks. Hum Brain Mapp 38:4078-4087, 2017. © 2017 Wiley Periodicals, Inc.

Functional and structural plasticity in the primary somatosensory cortex associated with chronic pain

Tissue or nerve injury induces widespread plastic changes from the periphery and spinal cord up to the cortex, resulting in chronic pain. Although many clinicians and researchers have extensively studied altered nociceptive signaling and neural circuit plasticity at the spinal cord level, effective treatments to ameliorate chronic pain are still insufficient. For about the last two decades, the rapid development in macroscopic brain imaging studies on humans and animal models have revealed maladaptive plastic changes in the 'pain matrix' brain regions, which may subsequently contribute to chronic pain. Among these brain regions, our group has concentrated for many years on the primary somatosensory (S1) cortex with a help of advanced imaging techniques and has found the functional and structural changes in neurons/glia as well as individual synapses in the S1 cortex during chronic pain. Taken together, it is now believed that such S1 plasticity is one of the causes for chronic pain, not a simple and passive epiphenomenon following tissue/nerve injury as previously thought. In this small review, we discuss the relation of plasticity in the S1 cortex with chronic pain, based on clinical trials and experimental studies conducted on this field. This article is part of the special article series "Pain".

Cortical Spreading Depression Closes Paravascular Space and Impairs Glymphatic Flow: Implications for Migraine Headache

Functioning of the glymphatic system, a network of paravascular tunnels through which cortical interstitial solutes are cleared from the brain, has recently been linked to sleep and traumatic brain injury, both of which can affect the progression of migraine. This led us to investigate the connection between migraine and the glymphatic system. Taking advantage of a novel in vivo method we developed using two-photon microscopy to visualize the paravascular space (PVS) in naive uninjected mice, we show that a single wave of cortical spreading depression (CSD), an animal model of migraine aura, induces a rapid and nearly complete closure of the PVS around surface as well as penetrating cortical arteries and veins lasting several minutes, and gradually recovering over 30 min. A temporal mismatch between the constriction or dilation of the blood vessel lumen and the closure of the PVS suggests that this closure is not likely to result from changes in vessel diameter. We also show that CSD impairs glymphatic flow, as indicated by the reduced rate at which intraparenchymally injected dye was cleared from the cortex to the PVS. This is the first observation of a PVS closure in connection with an abnormal cortical event that underlies a neurological disorder. More specifically, the findings demonstrate a link between the glymphatic system and migraine, and suggest a novel mechanism for regulation of glymphatic flow.SIGNIFICANCE STATEMENT Impairment of brain solute clearance through the recently described glymphatic system has been linked with traumatic brain injury, prolonged wakefulness, and aging. This paper shows that cortical spreading depression, the neural correlate of migraine aura, closes the paravascular space and impairs glymphatic flow. This closure holds the potential to define a novel mechanism for regulation of glymphatic flow. It also implicates the glymphatic system in the altered cortical and endothelial functioning of the migraine brain.

Altered brainstem anatomy in migraine

Background

The exact mechanisms responsible for migraine remain unknown, although it has been proposed that changes in brainstem anatomy and function, even between attacks, may contribute to the initiation and maintenance of headache during migraine attacks. The aim of this investigation is to use brainstem-specific analyses of anatomical and diffusion weighted images to determine if the trigeminal system displays altered structure in individuals with migraine.

Methods

Voxel-based morphometry of T1-weighted anatomical images (57 controls, 24 migraineurs) and diffusion tensor images (22 controls, 24 migraineurs) were used to assess brainstem anatomy in individuals with migraine compared with controls.

Results

We found grey matter volume decreases in migraineurs in the spinal trigeminal nucleus and dorsomedial pons. In addition, reduced grey matter volume and increased free water diffusivity occurred in areas of the descending pain modulatory system, including midbrain periaqueductal gray matter, dorsolateral pons, and medullary raphe. These changes were not correlated to migraine frequency, duration, intensity or time to next migraine.

Conclusion

Brainstem anatomy changes may underlie changes in activity that result in activation of the ascending trigeminal pathway and the perception of head pain during a migraine attack.

The sensorimotor network dysfunction in migraineurs without aura: a resting-state fMRI study

Migraine is a common recurrent neurological disorder combining nausea, vomiting, and hypersensitivities to visual, auditory, olfactory and somatosensory stimuli. However, the dysfunction of the sensorimotor network in migraineurs has not been well clarified. In the present study, we evaluated the dysfunction of the sensorimotor network in 30 migraineurs without aura and in 31 controls by combining regional homogeneity (ReHo), amplitudes of low-frequency fluctuation (ALFF) and degree centrality (DC) analysis methods based on resting-state fMRI. A seed-based functional connectivity (FC) analysis was used to investigate whether the dysfunctional areas within the sensorimotor network exhibited abnormal FC with other brain areas. Compared to the controls, the migraineurs without aura exhibited significantly smaller ReHo, ALFF and DC values in the primary somatosensory cortex (S1) and right premotor cortex (PMC). The migraineurs showed weaker FC between the S1 and brain areas within the pain intensity and spatial discrimination pathways and trigemino-thalamo-cortical nociceptive pathway. We proposed that the dysfunction of the S1 and PMC and the decreased FC between the S1 and brain areas in migraineurs without aura may disrupt the discrimination of sensory features of pain and affect nociception pathways, and would be involved in the dysfunctional mechanism in migraine.

Short-duration therapeutic massage reduces postural upper trapezius muscle activity

Massage therapy has historically been used as a therapeutic treatment to help reduce pain and promote relaxation. The aim of this study was to investigate the effect of therapeutic massage on the upper trapezius muscles, which are commonly associated with increased muscle tension. This was a randomized crossover study. Seventeen healthy individuals (nine women; 24.5±4.0 years) participated in the study. All individuals participated in two sessions that were held 24 h apart. In one of the sessions, the participants received a moderate pressure massage applied to the shoulders and neck. In the other session, participants sat quietly. The order of the sessions was counterbalanced across participants. Muscle activity, as measured by surface electromyography, of the upper trapezius muscles was recorded. The amount of muscle activity change following massage was compared with the change in muscle activity following quiet sitting. Muscle activity of the upper trapezius reduced significantly (19.3%; P=0.004) following massage compared with muscle activity following quiet sitting (1.0%). Our findings suggest that short-duration moderate pressure massage leads to a reduction in upper trapezius muscle activity. This result has potential implications for clinical populations such as those with chronic neck pain.

Cortical thickness and functional connectivity abnormality in chronic headache and low back pain patients

This study aims to characterize the psychological wellbeing of chronic headache (CH) patients, to identify cortical structural abnormalities and any associations of those abnormalities with resting state functional connectivity (rsFC), and to determine whether such rsFC abnormality is specific to CH patients. Compared with healthy controls (CON_CH ), CH patients suffered from mild depression, sleep disturbances, and relatively poor quality of life. CH patients also exhibited widespread cortical thickness (CT) abnormalities in left premotor (BA6), right primary somatosensory (S1) and right prefrontal (BA10) cortices, as well as in regions of default mode and executive control networks. Using cortical regions with thickness abnormality as seeds, we found cortical region pairs showed strengthened rsFC in CH patients. Using the same seeds, rsFC analysis from chronic low back pain (CLBP) patients and their controls (CON_CLBP ) identified abnormalities in non-overlapping cortical region pairs. Direct comparison of rsFC between CH and CLBP patients revealed significantly differences in thirteen cortical region pairs, including the four identified in CH and CON_CH comparison. Across all three groups (CH, CLBP and CON), the rsFC between left multisensory association area (BA39) and left posterior cingulate cortex (BA23) differed significantly. Eight regions showed CT abnormality in CLBP patients, two of which overlapped with those of CH patients. Our observations support the notion that CH and CLBP pain are pathological conditions, under which the brain develops distinct widespread structural and functional abnormalities. CH and CLBP groups share some similar structural abnormalities, but rsFC abnormalities in several cortical region pairs appear to be pathology-specific. Hum Brain Mapp 38:1815-1832, 2017. © 2017 Wiley Periodicals, Inc.

Multisensory Integration in Migraine: Recent Developments

There are well-documented unimodal sensory differences in migraine compared to control groups both during, and between migraine attacks. There is also some evidence of multisensory integration differences in migraine groups compared to control groups, however the literature on this topic is more limited. There are interesting avenues in the area of visual–vestibular integration, which might have practical implications, e.g., motion sickness and nausea in migraine. Recent work has been investigating the possibility of visual–auditory integration in migraine, and found possible differences in the susceptibility to the sound-induced flash illusion in particular, which could give insights into relative excitability of different areas of the cortex, and also into mechanisms for the illusions themselves. This review updates the most recent literature and also highlights potentially fruitful areas of research to understand one of the most common neurological disorders.

Brain Changes in Responders vs. Non-Responders in Chronic Migraine: Markers of Disease Reversal

The aim of this study was to identify structural and functional brain changes that accompanied the transition from chronic (CM; ≥15 headache days/month) to episodic (EM; <15 headache days/month) migraine following prophylactic treatment with onabotulinumtoxinA (BoNT-A). Specifically, we examined whether CM patients responsive to prophylaxis (responders; n = 11), as evidenced by a reversal in disease status (defined by at least a 50% reduction in migraine frequency and <15 headache days/month), compared to CM patients whose migraine frequency remained unchanged (non-responders; n = 12), showed differences in cortical thickness using surface-based morphometry. We also investigated whether areas showing group differences in cortical thickness displayed altered resting-state functional connectivity (RS-FC) using seed-to-voxel analyses. Migraine characteristics measured across groups included disease duration, pain intensity and headache frequency. Patient reports of headache frequency over the 4 weeks prior to (pre-treatment) and following (post-treatment) prophylaxis were compared (post minus pre) and this measure served as the clinical endpoint that determined group assignment. All patients were scanned within 2 weeks of the post-treatment visit. Results revealed that responders showed significant cortical thickening in the right primary somatosensory cortex (SI) and anterior insula (aINS), and left superior temporal gyrus (STG) and pars opercularis (ParsOp) compared to non-responders. In addition, disease duration was negatively correlated with cortical thickness in fronto-parietal and temporo-occipital regions in responders but not non-responders, with the exception of the primary motor cortex (MI) that showed the opposite pattern; disease duration was positively associated with MI cortical thickness in responders versus non-responders. Our seed-based RS-FC analyses revealed anti-correlations between the SI seed and lateral occipital (LOC) and dorsomedial prefrontal cortices (DMPFC) in responders, whereas non-responders showed increased connectivity between the ParsOp seed and LOC. Overall, our findings revealed distinct morphometric and functional brain changes in CM patients that reverted to EM following prophylactic treatment compared to CM patients that showed no change in disease status. Elucidating the CNS changes involved in disease reversal may be critical to discovering interventions that prevent or slow the progression of CM. Such changes may aid in the evaluation of treatments as well as provide markers for disease “de-chronification”.

Different mean thickness implicates involvement of the cortex in migraine

The results of neuroimaging studies on migraines have shown that the functions and functional connectivity networks of some brain regions are altered in migraine patients, and different brain structure volumes have also been observed in recent years. However, it is still not known whether the mean thickness of the cortex is different in migraine patients.A total of 48 migraine without aura (MWoA) patients in interictal phase and 48 healthy controls were enrolled in this study. All subjects received neurological and magnetic resonance imaging (MRI) examinations. Automatic segmentation processing of high-resolution MRI structure images was performed using FreeSurfer software.The mean cortical thickness of many brain regions in the frontal lobe, temporal lobe, occipital lobe, parietal lobe, and insula in the migraine patient group was significantly decreased compared with that in the healthy control group. The mean cortical thickness of the insula anterior was positively correlated with the duration of the disease course, while the mean cortical thickness of insula superior and insula inferior was negatively correlated with the duration of the disease course.The results showed that MWoA results from a complex interactive reaction involving many brain regions and many brain network systems together. However, it is still not clear whether the difference in the brain structure of migraine patients is the result or the cause of headache, which is a topic that must be better elucidated. Therefore, longitudinal neuroimaging studies on migraine patients with large samples sizes should be performed using more advanced neuroimaging techniques.

Current Understanding on Pain Mechanism in Migraine and Cluster Headache

CONTEXT

Migraine and cluster headache are undoubtedly painful conditions. The respective pathogenesis of these two conditions is incompletely understood. In both cases, the treatments used have largely been empirical and have relied to a much lesser extent on our understanding of the mechanisms causing pain. We hereby review the pain mechanisms in migraine and cluster headache, two of the commonest primary headache disorders.

EVIDENCE ACQUISITION

A review of the English literature was conducted by searching PubMed for studies on pain mechanism in migraine and cluster headache. We entered [migraine] and [pain mechanism] in Pubmed and 488 articles were obtained. Articles were then included according to their relevance to the topic. Similarly, [cluster headache] and [pain mechanism] revealed 79 search results.

RESULTS

There is evidence that the trigeminovascular system and neurogenic inflammation play important roles, together with certain areas of the brain, leading to these conditions being termed 'neurovascular headaches'. Functional imaging findings suggest a possible role of the dorsolateral pons in generating migraine attacks while the role of the hypothalamus in cluster headache is more firmly established.

CONCLUSIONS

Migraine and cluster headache have complex pathophysiologies. The exact mechanism causing pain in both conditions is incompletely understood and more research needs to be undertaken in this area.

Multivariate morphological brain signatures predict patients with chronic abdominal pain from healthy control subjects

Irritable bowel syndrome (IBS) is the most common chronic visceral pain disorder. The pathophysiology of IBS is incompletely understood; however, evidence strongly suggests dysregulation of the brain-gut axis. The aim of this study was to apply multivariate pattern analysis to identify an IBS-related morphometric brain signature that could serve as a central biological marker and provide new mechanistic insights into the pathophysiology of IBS. Parcellation of 165 cortical and subcortical regions was performed using FreeSurfer and the Destrieux and Harvard-Oxford atlases. Volume, mean curvature, surface area, and cortical thickness were calculated for each region. Sparse partial least squares discriminant analysis was applied to develop a diagnostic model using a training set of 160 females (80 healthy controls and 80 patients with IBS). Predictive accuracy was assessed in an age-matched holdout test set of 52 females (26 healthy controls and 26 patients with IBS). A 2-component classification algorithm comprising the morphometry of (1) primary somatosensory and motor regions and (2) multimodal network regions explained 36% of the variance. Overall predictive accuracy of the classification algorithm was 70%. Small effect size associations were observed between the somatosensory and motor signature and nongastrointestinal somatic symptoms. The findings demonstrate that the predictive accuracy of a classification algorithm based solely on regional brain morphometry is not sufficient, but they do provide support for the utility of multivariate pattern analysis for identifying meaningful neurobiological markers in IBS.

Female migraineurs show lack of insular thinning with age

Gray matter loss in cortical regions is a normal ageing process for the healthy brain. There have been few studies on the process of ageing of the brain in chronic neurological disorders. In this study, we evaluated changes in the cortical thickness by age in 92 female subjects (46 patients with migraine and 46 healthy controls) using high-field magnetic resonance imaging. The results indicate that in contrast to healthy subjects, migraineurs show a lack of thinning in the insula by age. The functional significance of the lack of thinning is unknown, but it may contribute to the overall cortical hyperexcitability of the migraine brain because the region is tightly involved in a number of major brain networks involved in interoception, salience, nociception, and autonomic function, including the default mode network.

Primary Somatosensory Cortices Contain Altered Patterns of Regional Cerebral Blood Flow in the Interictal Phase of Migraine

The regulation of cerebral blood flow (CBF) is a complex integrated process that is critical for supporting healthy brain function. Studies have demonstrated a high incidence of alterations in CBF in patients suffering from migraine with and without aura during different phases of attacks. However, the CBF data collected interictally has failed to show any distinguishing features or clues as to the underlying pathophysiology of the disease. In this study we used the magnetic resonance imaging (MRI) technique—arterial spin labeling (ASL)—to non-invasively and quantitatively measure regional CBF (rCBF) in a case-controlled study of interictal migraine. We examined both the regional and global CBF differences between the groups, and found a significant increase in rCBF in the primary somatosensory cortex (S1) of migraine patients. The CBF values in S1 were positively correlated with the headache attack frequency, but were unrelated to the duration of illness or age of the patients. Additionally, 82% of patients reported skin hypersensitivity (cutaneous allodynia) during migraine, suggesting atypical processing of somatosensory stimuli. Our results demonstrate the presence of a disease-specific functional deficit in a known region of the trigemino-cortical pathway, which may be driven by adaptive or maladaptive functional plasticity. These findings may in part explain the altered sensory experiences reported between migraine attacks.

The impact of cognitive symptoms on migraine attack-related disability

Background

The socio-economic impact of migraine is mostly related to work loss either by absenteeism or decreased work performance. Migraine-associated cognitive dysfunction during an attack may contribute to these difficulties.

Objective

The objective of this article is to analyze the presence and relevance of cognitive symptoms during migraine attacks and to relate their intensity and symptom-related disability with other migraine-defining symptoms.

Methods

Consecutive migraine patients of a headache clinic completed diaries scoring each migraine symptom (including cognitive symptoms) intensity and symptom-related disability.

Results

Of 100 consecutive patients included in this study, 34 (all females, age average 31.8 ± 8.8 years) returned information on 229 attacks, on average 6.7 per participant. Every symptom’s intensity was always rated slightly higher than the disability it caused. Pain was the symptom scored with the highest intensity and disability, followed by cognitive symptoms (difficulty in thinking and worsening with mental effort) and photo- and phonophobia. Scoring was independent of any of the clinical variables. Attack intensity and disability scores correlated with intensity and disability from pain and from worsening with mental effort.

Conclusions

Attack-related cognitive symptoms are intense and disabling. Some attack-related cognitive symptoms correlate to intensity and disability subjectively attributed to the migraine attack. Cognitive performance should be addressed as a valuable secondary endpoint in trials of acute migraine treatment.