Migraine attacks the Basal Ganglia

Resting-state brain activity as a biomarker of chronic pain impairment and a mediator of its association with pain resilience

Past cross-sectional chronic pain studies have revealed aberrant resting-state brain activity in regions involved in pain processing and affect regulation. However, there is a paucity of longitudinal research examining links of resting-state activity and pain resilience with changes in chronic pain outcomes over time. In this prospective study, we assessed the status of baseline (T1) resting-state brain activity as a biomarker of later impairment from chronic pain and a mediator of the relation between pain resilience and impairment at follow-up. One hundred forty-two adults with chronic musculoskeletal pain completed a T1 assessment comprising a resting-state functional magnetic resonance imaging scan based on regional homogeneity (ReHo) and self-report measures of demographics, pain characteristics, psychological status, pain resilience, pain severity, and pain impairment. Subsequently, pain impairment was reassessed at a 6-month follow-up (T2). Hierarchical multiple regression and mediation analyses assessed relations of T1 ReHo and pain resilience scores with changes in pain impairment. Higher T1 ReHo values in the right caudate nucleus were associated with increased pain impairment at T2, after controlling for all other statistically significant self-report measures. ReHo also partially mediated associations of T1 pain resilience dimensions with T2 pain impairment. T1 right caudate nucleus ReHo emerged as a possible biomarker of later impairment from chronic musculoskeletal pain and a neural mechanism that may help to explain why pain resilience is related to lower levels of later chronic pain impairment. Findings provide empirical foundations for prospective extensions that assess the status of ReHo activity and self-reported pain resilience as markers for later impairment from chronic pain and targets for interventions to reduce impairment. PRACTITIONER POINTS: Resting-state markers of impairment: Higher baseline (T1) regional homogeneity (ReHo) values, localized in the right caudate nucleus, were associated with exacerbations in impairment from chronic musculoskeletal pain at a 6-month follow-up, independent of T1 demographics, pain experiences, and psychological factors. Mediating role of ReHo values: ReHo values in the right caudate nucleus also mediated the relationship between baseline pain resilience levels and later pain impairment among participants. Therapeutic implications: Findings provide empirical foundations for research extensions that evaluate (1) the use of resting-state activity in assessment to identify people at risk for later impairment from pain and (2) changes in resting-state activity as biomarkers for the efficacy of treatments designed to improve resilience and reduce impairment among those in need.

Enhanced audiovisual associative pair learning in migraine without aura in adult patients: An unexpected finding

BACKGROUND

Altered sensory processing in migraine has been demonstrated by several studies in unimodal, and especially visual, tasks. While there is some limited evidence hinting at potential alterations in multisensory processing among migraine sufferers, this aspect remains relatively unexplored. This study investigated the interictal cognitive performance of migraine patients without aura compared to matched controls, focusing on associative learning, recall, and transfer abilities through the Sound-Face Test, an audiovisual test based on the principles of the Rutgers Acquired Equivalence Test.

MATERIALS AND METHODS

The performance of 42 volunteering migraine patients was compared to the data of 42 matched controls, selected from a database of healthy volunteers who had taken the test earlier. The study aimed to compare the groups' performance in learning, recall, and the ability to transfer learned associations.

RESULTS

Migraine patients demonstrated significantly superior associative learning as compared to controls, requiring fewer trials, and making fewer errors during the acquisition phase. However, no significant differences were observed in retrieval error ratios, generalization error ratios, or reaction times between migraine patients and controls in later stages of the test.

CONCLUSION

The results of our study support those of previous investigations, which concluded that multisensory processing exhibits a unique pattern in migraine. The specific finding that associative audiovisual pair learning is more effective in adult migraine patients than in matched controls is unexpected. If the phenomenon is not an artifact, it may be assumed to be a combined result of the hypersensitivity present in migraine and the sensory threshold-lowering effect of multisensory integration.

High-definition tDCS over primary motor cortex modulates brain signal variability and functional connectivity in episodic migraine

OBJECTIVE

This study investigated how high-definition transcranial direct current stimulation (HD-tDCS) over the primary motor cortex (M1) affects brain signal variability and functional connectivity in the trigeminal pain pathway, and their association with changes in migraine attacks.

METHODS

Twenty-five episodic migraine patients were randomized for ten daily sessions of active or sham M1 HD-tDCS. Resting-state blood-oxygenation-level-dependent (BOLD) signal variability and seed-based functional connectivity were assessed pre- and post-treatment. A mediation analysis was performed to test whether BOLD signal variability mediates the relationship between treatment group and moderate-to-severe headache days.

RESULTS

The active M1 HD-tDCS group showed reduced BOLD variability in the spinal trigeminal nucleus (SpV) and thalamus, but increased variability in the rostral anterior cingulate cortex (rACC) compared to the sham group. Connectivity decreased between medial pulvinar-temporal pole, medial dorsal-precuneus, and the ventral posterior medial nucleus-SpV, but increased between the rACC-amygdala, and the periaqueductal gray-parahippocampal gyrus. Changes in medial pulvinar variability mediated the reduction in moderate-to-severe headache days at one-month post-treatment.

CONCLUSIONS

M1 HD-tDCS alters BOLD signal variability and connectivity in the trigeminal somatosensory and modulatory pain system, potentially alleviating migraine headache attacks.

SIGNIFICANCE

M1 HD-tDCS realigns brain signal variability and connectivity in migraineurs closer to healthy control levels.

Models of Trigeminal Activation: Is There an Animal Model of Migraine?

Migraine, recognized as a severe headache disorder, is widely prevalent, significantly impacting the quality of life for those affected. This article aims to provide a comprehensive review of the application of animal model technologies in unraveling the pathomechanism of migraine and developing more effective therapies. It introduces a variety of animal experimental models used in migraine research, emphasizing their versatility and importance in simulating various aspects of the condition. It details the benefits arising from the utilization of these models, emphasizing their role in elucidating pain mechanisms, clarifying trigeminal activation, as well as replicating migraine symptoms and histological changes. In addition, the article consciously acknowledges the inherent limitations and challenges associated with the application of animal experimental models. Recognizing these constraints is a fundamental step toward fine-tuning and optimizing the models for a more accurate reflection of and translatability to the human environment. Overall, a detailed and comprehensive understanding of migraine animal models is crucial for navigating the complexity of the disease. These findings not only provide a deeper insight into the multifaceted nature of migraine but also serve as a foundation for developing effective therapeutic strategies that specifically address the unique challenges arising from migraine pathology.

Brain structural and functional abnormalities in patients with tension-type headache: A systematic review of magnetic resonance imaging studies

Tension-type headache (TTH) stands as the most prevalent form of headache, yet an adequate understanding of its underlying mechanisms remains elusive. This article endeavors to comprehensively review structural and functional magnetic resonance imaging (MRI) studies investigating TTH patients, to gain valuable insights into the pathophysiology of TTH, and to explore new avenues for enhanced treatment strategies. We conducted a systematic search to identify relevant articles examining brain MRI disparities between TTH individuals and headache-free controls (HFC). Fourteen studies, encompassing 312 diagnosed TTH patients, were selected for inclusion. Among these, eight studies utilized conventional MRI, one employed diffusion tensor imaging, and five implemented various functional MRI modalities. Consistent findings across these studies revealed a notable increase in white matter hyperintensity (WMH) in TTH patients. Furthermore, the potential involvement of the specific brain areas recognized to be involved in different dimensions of pain perception including cortical regions (anterior and posterior cingulate cortex, prefrontal cortex, anterior and posterior insular cortex), subcortical regions (thalamus, caudate, putamen, and parahippocampus), cerebellum in TTH pathogenesis was identified. However, no significant association was established between TTH and intracranial abnormalities or total intracranial volume. In conclusion, these findings support the hypotheses regarding the role of central mechanisms in TTH pathophysiology and offer probable brain regions implicated in these mechanisms. Due to the scarce data on the precise role of these regions in the TTH, further preclinical and clinical investigations should be done to advance our knowledge and enhance targeted therapeutic options of TTH.

Suboptimal multisensory processing in pediatric migraine without aura: a comparative, cross-sectional study

Alterations of sensory processing in migraine are well known. There is some evidence to suggest that multisensory processing is altered in migraine as well, but the area is underexplored, especially regarding pediatric migraine. A visual and an audiovisual version of the Rutgers Acquired Equivalence Test paradigm was administered to pediatric patients with migraine without aura (aged 7-17.5 years) and to age- and sex-matched controls. The application of audiovisual stimuli significantly facilitated associative pair learning in migraine-free children and adolescents, but not in pediatric migraine patients. The results of this study corroborate the hypothesis that multisensory processing is altered in pediatric migraine without aura.

Trigeminocervical pain sensitivity during the migraine cycle depends on headache frequency

OBJECTIVE

This experimental study aimed to assess pain sensitivity in low-frequency episodic migraine (LFEM), high-frequency episodic migraine (HFEM), and chronic migraine (CM) patients across the different phases of the migraine cycle.

METHOD

In this observational, experimental study, clinical characteristics (diary and time from the last/next headache attack), and quantitative sensory testing (QST) (wind-up pain ratio (WUR) and pressure pain threshold (PPT) from the trigeminal area and PPT from the cervical spine) was performed. LFEM, HFEM, and CM were assessed in each of the 4 migraine phases (HFEM and LFEM: interictal, preictal, ictal, and postictal; CM: interictal and ictal) and compared vs. each other's (matched for the phase) and controls.

RESULTS

A total of 56 controls, 105 LFEM, 74 HFEM, and 32 CM were included. No differences in QST parameters were observed between LFEM, HFEM, and CM in any of the phases. During the interictal phase and when comparing with controls the following were found: 1) LFEM had lower trigeminal PPT (p = 0.001) and 2) lower cervical PPT (p = 0.001). No differences were observed between HFEM or CM and healthy controls. During the ictal phase and when comparing with controls the following were found: HFEM and CM had 1) lower trigeminal PPTs (HFEM p = 0.001; CM = p < 0.001), 2) lower cervical PPT s (HFEM p = 0.007; CM p < 0.001), and 3) higher trigeminal WUR (HFEM p = 0.001, CM p = 0.006). No differences were observed between LFEM and healthy controls. During the preictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.007), 2) HFEM had lower trigeminal (p = 0.013) and 3) HFEM had lower cervical (p = .006) PPTs. During the postictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.003), 2) HFEM had lower trigeminal PPT (p = 0.005), and 3) and HFEM had lower cervical (p = 0.007) PPTs.

CONCLUSION

This study suggested that HFEM patients have a sensory profile matching CM better than LFEM. When assessing pain sensitivity in migraine populations, the phase with respects to headache attacks is of utmost importance and can explain the inconsistency in pain sensitivity data reported in the literature.

Peripherally acting anti-CGRP monoclonal antibodies alter cortical gray matter thickness in migraine patients: A prospective cohort study

Migraine is underpinned by central nervous system neuroplastic alterations thought to be caused by the repetitive peripheral afferent barrage the brain receives during the headache phase (cortical hyperexcitability). Calcitonin gene-related peptide monoclonal antibodies (anti-CGRP-mAbs) are highly effective migraine preventative treatments. Their ability to alter brain morphometry in treatment-responders vs. non-responders is not well understood. Our aim was to determine the effects of the anti-CGRP-mAb galcanezumab on cortical thickness after 3-month treatment of patients with high-frequency episodic or chronic migraine. High-resolution magnetic resonance imaging was performed pre- and post-treatment in 36 migraine patients. In this group, 19 patients were classified responders (≥50 % reduction in monthly migraine days) and 17 were considered non-responders (<50 % reduction in monthly migraine days). Following cross-sectional processing to analyze the baseline differences in cortical thickness, two-stage longitudinal processing and symmetrized percent change were conducted to investigate treatment-related brain changes. At baseline, no significant differences were found between the responders and non-responders. After 3-month treatment, decreased cortical thickness (compared to baseline) was observed in the responders in regions of the somatosensory cortex, anterior cingulate cortex, medial frontal cortex, superior frontal gyrus, and supramarginal gyrus. Non-responders demonstrated decreased cortical thickness in the left dorsomedial cortex and superior frontal gyrus. We interpret the cortical thinning seen in the responder group as suggesting that reduction in head pain could lead to changes in neural swelling and dendritic complexity and that such changes reflect the recovery process from maladaptive neural activity. This conclusion is further supported by our recent study showing that 3 months after treatment initiation, the incidence of premonitory symptoms and prodromes that are followed by headache decreases but not the incidence of the premonitory symptoms or prodromes themselves (that is, cortical thinning relates to reductions in the nociceptive signals in the responders). We speculate that a much longer recovery period is required to allow the brain to return to a more 'normal' functioning state whereby prodromes and premonitory symptoms no longer occur.

Migraine: Advances in the Pathogenesis and Treatment

This article presents a comprehensive review on migraine, a prevalent neurological disorder characterized by chronic headaches, by focusing on their pathogenesis and treatment advances. By examining molecular markers and leveraging imaging techniques, the research identifies key mechanisms and triggers in migraine pathology, thereby improving our understanding of its pathophysiology. Special emphasis is given to the role of calcitonin gene-related peptide (CGRP) in migraine development. CGRP not only contributes to symptoms but also represents a promising therapeutic target, with inhibitors showing effectiveness in migraine management. The article further explores traditional medical treatments, scrutinizing the mechanisms, benefits, and limitations of commonly prescribed medications. This provides a segue into an analysis of emerging therapeutic strategies and their potential to enhance migraine management. Finally, the paper delves into neuromodulation as an innovative treatment modality. Clinical studies indicating its effectiveness in migraine management are reviewed, and the advantages and limitations of this technique are discussed. In summary, the article aims to enhance the understanding of migraine pathogenesis and present novel therapeutic possibilities that could revolutionize patient care.

Increased iron deposition in nucleus accumbens associated with disease progression and chronicity in migraine

BACKGROUND

Migraine is one of the world's most prevalent and disabling diseases. Despite huge advances in neuroimaging research, more valuable neuroimaging markers are still urgently needed to provide important insights into the brain mechanisms that underlie migraine symptoms. We therefore aim to investigate the regional iron deposition in subcortical nuclei of migraineurs as compared to controls and its association with migraine-related pathophysiological assessments.

METHODS

A total of 200 migraineurs (56 chronic migraine [CM], 144 episodic migraine [EM]) and 41 matched controls were recruited. All subjects underwent MRI and clinical variables including frequency/duration of migraine, intensity of migraine, 6-item Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS), and Pittsburgh Sleep Quality Index (PSQI) were recorded. Quantitative susceptibility mapping was employed to quantify the regional iron content in subcortical regions. Associations between clinical variables and regional iron deposition were studied as well.

RESULTS

Increased iron deposition in the putamen, caudate, and nucleus accumbens (NAC) was observed in migraineurs more than controls. Meanwhile, patients with CM had a significantly higher volume of iron deposits compared to EM in multiple subcortical nuclei, especially in NAC. Volume of iron in NAC can be used to distinguish patients with CM from EM with a sensitivity of 85.45% and specificity of 71.53%. As the most valuable neuroimaging markers in all of the subcortical nuclei, higher iron deposition in NAC was significantly associated with disease progression, and higher HIT-6, MIDAS, and PSQI.

CONCLUSIONS

These findings provide evidence that iron deposition in NAC may be a biomarker for migraine chronicity and migraine-related dysfunctions, thus may help to understand the underlying vascular and neural mechanisms of migraine.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT04939922.

Galcanezumab effects on incidence of headache after occurrence of triggers, premonitory symptoms, and aura in responders, non-responders, super-responders, and super non-responders

BACKGROUND

The goal of this observational, open-label, cohort study was to determine whether prophylactic migraine treatment with galcanezumab, a peripherally acting drug, alters the incidence of premonitory symptoms, and/or occurrence of headache after exposure to triggers or aura episodes in treatment-responders (≥ 50% reduction in monthly migraine days [MMD]), super-responders (≥ 70%), non-responders (< 50%) and super non-responders (< 30%).

METHODS

Participants were administered electronic daily headache diaries to document migraine days and associated symptoms one month before and during the three months of treatment. Questionnaires were used to identify conscious prodromal and trigger events that were followed by headache prior to vs. after 3 months of treatment.

RESULTS

After 3 months of galcanezumab treatment, (a) the incidence of premonitory symptoms that were followed by headache decreased by 48% in the 27 responders vs. 28% in the 19 non-responders, and by 50% in the 11 super-responders vs. 12% in the 8 super non-responders; (b) the incidence of visual and sensory aura that were followed by headache was reduced in responders, non-responders, and super-responders, but not in super non-responders; (c) the number of triggers followed by headache decreased by 38% in responders vs. 13% in non-responders, and by 31% in super-responders vs. 4% in super non-responders; and (d) some premonitory symptoms (e.g., cognitive impairment, irritability, fatigue) and triggers (e.g., stress, sleeping too little, bright light, aura) were followed by headache only in super non-responders.

CONCLUSIONS

Mechanistically, these findings suggest that even a mild decrease in migraine frequency is sufficient to partially reverse the excitability and responsivity of neurons involved in the generation of certain triggers and potentially premonitory symptoms of migraine.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04271202. Registration date: February 10, 2020.

Altered functional connectivity of the right caudate nucleus in chronic migraine: a resting-state fMRI study

BACKGROUND

The definitive pathogenic mechanisms underlying chronic migraine (CM) remain unclear. Mounting evidence from functional and structural magnetic resonance imaging (MRI) studies suggests that the caudate nucleus (CN) plays a role in the cognitive, sensory, and emotional integration of pain information in patients with migraine. However, evidence concerning the role played by CN in CM patients is limited. Here, we used the CN as the seed to explore patterns of functional connectivity (FC) among healthy controls (HCs), patients with episodic migraine (EM), and patients with CM.

METHODS

We included 25 HCs, 23 EM patients, and 46 CM patients in this study. All participants underwent resting-state functional MRI scans on a GE 3.0T MRI system. We performed seed-based FC analyses among the three groups using the bilateral CNs as seeds. We also compared the subgroups of CM (with and without medication overuse headache, males and females) and performed Pearson's correlation analyses between FC values and the clinical features of CM patients.

RESULTS

FC values between the right CN and five clusters (mainly involved in emotion, cognition, and sensory-related brain regions) were higher in CM patients than in HCs. Compared to EM patients, enhanced FC values between the bilateral precuneus, left anterior cingulate gyrus, right middle cingulate cortex, right lingual gyrus, and right CN were shown in the CM patients. There were no significant differences between CM patients with and without MOH, males and females. FC values between the bilateral calcarine cortex, lingual gyrus, and right CN were positively correlated with body mass index. Moreover, right CN-related FC values in the left calcarine cortex and right lingual gyrus were inversely correlated with visual analogue scale scores for headaches.

CONCLUSION

Our results revealed abnormal right CN-based FC values in CM patients, suggesting dysfunction of brain networks associated with pain perception and multi-regulation (emotion, cognition, and sensory). Aberrant FC of the CN can provide potential neuroimaging markers for the diagnosis and treatment of CM.

Meta-analytical evidence of functional and structural abnormalities associated with pain processing in migraine patients: An activation likelihood estimation

BACKGROUND

Migraine is a primary headache disorder that causes debilitating throbbing pain. Several functional MRI (fMRI) and voxel-based morphometry (VBM) studies have been used to investigate the structural and functional alteration in migraine. Here, we aim to study the converged brain regions of functional and structural abnormalities in gray matter volume (GMV) associated with pain processing and management in migraineurs and healthy controls (HC).

METHODS

A systematic search through PubMed and Sleuth was carried out for peer-reviewed functional and structural neuroimaging studies on migraine patients and HC yielded a total of 1136 studies. We performed an activation likelihood estimation (ALE) meta-analysis on VBM and pain stimulation task-based fMRI studies to investigate the converged areas of GMV and functional abnormalities between migraineurs and HC. We performed two subgroup analyses between migraine with aura (MwA) and migraine without aura (MwoA) relative to HC, and between chronic migraine (CM) and episodic migraine (EM) compared to HC.

RESULTS

The total sample included 16 fMRI and 22 VBM studies, consisting of 1295 migraine patients, compared to 995 HC. In fMRI analysis, ALE maps for pain stimulation tasks revealed hyperactivation in migraineurs in the substantia nigra compared to HC, whereas hypoactivation was seen in the cerebellum. For the VBM analysis, ALE clusters of increased GMV in migraineurs were observed in the parahippocampus and putamen nucleus. Whereas clusters of reduced GMV in migraineurs were seen in the frontal gyri. Compared to HC, MwoA patients showed a GMV reduction in the insula, and anterior cingulate, whereas MwA patients showed GMV reduction in the cerebellum, cingulate gyrus, and insula. CM patients showed decreased GMV in the precentral gyrus, whereas EM patients showed decreased GMV in the parahippocampus, and inferior frontal gyrus when compared to HC.

CONCLUSIONS

Our findings represent a potential biomarker for the diagnosis and management of migraine, by showing clustered brain regions of abnormal patterns of activation and GMV changes between migraineurs and HC which might be associated with hyposensitivity to pain in migraineurs. Further studies are required to determine disease progression or therapeutic interventions' effect on migraine.

Graph theory analysis identified two hubs that connect sensorimotor and cognitive and cortical and subcortical nociceptive networks in the non-human primate

Pain perception involves multiple brain regions and networks. Understanding how these brain networks work together is fundamental for appreciating network-wise changes reported in patients with chronic pain disorders. Parcellating pain related networks and understanding their causal relationships is the first step to understand how painful information is processed, integrated, and modulated, and it requires direct manipulation of specific brain regions. Nonhuman primates (NHP) offer an ideal model system to achieve these goals because cortical and subcortical regions in the NHP brain are established based on a variety of different types of data collected in a way that is not feasible or, at least, extremely difficult in humans (i.e., histology data, tract-tracing, intracerebral recordings). In addition, different methodological techniques can also help characterize and further understand these brain cortical and subcortical regions over the course of development. Here we used a heat nociceptive stimulation that is proven to elicit activity of nociceptive neurons in the cortex to refine and parcellate the whole brain nociceptive functional networks, to identify key network hubs, and to characterize network-wise temporal dynamic signatures using high-resolution fMRI. We first functionally localized 24 cortical and subcortical regions that responded to heat nociceptive stimuli (somatosensory area 1/2, area 3a/3b, S2, posterior insula (pIns), anterior insula, area 7b, posterior parietal cortex, anterior cingulate cortex (ACC), prefrontal cortex, caudate, and mediodorsal (MD) and ventral posterior lateral (VPL) thalamic nuclei) and used them as seeds in resting state fMRI (rsfMRI) data analysis. We applied both hierarchical clustering and graph-theory analyses of the pairwise rsfMRI correlation metrics and identified five cortical and one subcortical sub-networks: strong resting state functional connectivity (rsFC) between ACC and prefrontal regions, parietal cortex and area 7b, S2 and posterior insula, areas 3a/3b and 1/2 within the S1 cortex, and thalamic MD and caudate nuclei. The rsFC strengths between cortical areas within each subnetwork were significantly stronger than those between subcortical regions. Regions within each sub-network also exhibited highly correlated temporal dynamics at rest, but the overall dynamic patterns varied drastically across sub-networks. Graph-theory analysis identified the MD nucleus as a hub that connects subcortical and cortical nociceptive sub-networks. The S2-pIns connection joins the sensory and affective/cognitive sub-networks.

Neurophysiology of hypnosis in chronic pain: A review of recent literature

Chronic pain is a complex phenomenon which includes biological, psychological, and socio-professional factors that undermine patients' everyday life. Currently, only few patients significantly benefit from pharmacological treatments and many have to stop them because of negative side effects. Moreover, no medication or treatment addresses all aspects of chronic pain at once (i.e., sensations, emotions, behaviors, and cognitions), positioning chronic pain as an important public health issue and thus contributing to high health-care costs. Consequently, patients and health-care providers are increasingly turning to complementary non-pharmacological techniques such as hypnosis. Clinical research has demonstrated a decrease of pain perception, pain interference, depression and anxiety, and an increase in global quality of life when patients with chronic pain have benefited from hypnosis learning. Neuroimaging studies offer a possible explanation of these results by focusing on neural processes of pain modulation in chronic pain patients' brain. Studies conducted with chronic pain patients showed a modulation of pain matrix activity during hypnosis with a specific involvement of the anterior cingulate cortex (related to emotional and cognitive processing of pain). Therefore, hypnosis seems to act upon regions underlying emotion and cognition, with an influence on pain perception and emotional regulation. In this review, we propose to carry out a review of the recent literature on hypnosis in chronic pain management. A better understanding of the beneficial effects of hypnosis on chronic pain and its neurophysiology should enable more systematic use of this technique in the management of this complex health problem.

Cerebro-Cerebellar Networks in Migraine Symptoms and Headache

The cerebellum is associated with the biology of migraine in a variety of ways. Clinically, symptoms such as fatigue, motor weakness, vertigo, dizziness, difficulty concentrating and finding words, nausea, and visual disturbances are common in different types of migraine. The neural basis of these symptoms is complex, not completely known, and likely involve activation of both specific and shared circuits throughout the brain. Posterior circulation stroke, or neurosurgical removal of posterior fossa tumors, as well as anatomical tract tracing in animals, provided the first insights to theorize about cerebellar functions. Nowadays, with the addition of functional imaging, much progress has been done on cerebellar structure and function in health and disease, and, as a consequence, the theories refined. Accordingly, the cerebellum may be useful but not necessary for the execution of motor, sensory or cognitive tasks, but, rather, would participate as an efficiency facilitator of neurologic functions by improving speed and skill in performance of tasks produced by the cerebral area to which it is reciprocally connected. At the subcortical level, critical regions in these processes are the basal ganglia and thalamic nuclei. Altogether, a modulatory role of the cerebellum over multiple brain regions appears compelling, mainly by considering the complexity of its reciprocal connections to common neural networks involved in motor, vestibular, cognitive, affective, sensory, and autonomic processing—all functions affected at different phases and degrees across the migraine spectrum. Despite the many associations between cerebellum and migraine, it is not known whether this structure contributes to migraine initiation, symptoms generation or headache. Specific cerebellar dysfunction via genetically driven excitatory/inhibitory imbalances, oligemia and/or increased risk to white matter lesions has been proposed as a critical contributor to migraine pathogenesis. Therefore, given that neural projections and functions of many brainstem, midbrain and forebrain areas are shared between the cerebellum and migraine trigeminovascular pathways, this review will provide a synopsis on cerebellar structure and function, its role in trigeminal pain, and an updated overview of relevant clinical and preclinical literature on the potential role of cerebellar networks in migraine pathophysiology.

Migraine and peripheral pain models show differential alterations in neuronal complexity

Objective

Our laboratory has recently shown that there is a decrease in neuronal complexity in head pain processing regions in mouse models of chronic migraine‐associated pain and aura. Importantly, restoration of this neuronal complexity corresponds with anti‐migraine effects of known and experimental pharmacotherapies. The objective of the current study was to expand this work and examine other brain regions involved with pain or emotional processing. We also investigated the generalizability of our findings by analyzing neuronal cytoarchitectural changes in a model of complex regional pain syndrome (CRPS), a peripheral pain disorder.

Methods

We used the nitroglycerin (NTG) model of chronic migraine‐associated pain in which mice receive 10 mg/kg NTG every other day for 9 days. Cortical spreading depression (CSD), a physiological corelate of migraine aura, was evoked in anesthetized mice using KCl. CRPS was induced by tibial fracture followed by casting. Neuronal cytoarchitecture was visualized with Golgi stain and analyzed with Simple Neurite Tracer.

Results

In the NTG model, we previously showed decreased neuronal complexity in the trigeminal nucleus caudalis (TNC) and periaqueductal gray (PAG). In contrast, we found increased neuronal complexity in the thalamus and no change in the amygdala or caudate putamen in this study. Following CSD, we observed decreased neuronal complexity in the PAG, in line with decreases in the somatosensory cortex and TNC reported with this model previously. In the CRPS model there was decreased neuronal complexity in the hippocampus, as reported by others; increased complexity in the PAG; and no change within the somatosensory cortex.

Conclusions

Collectively these results demonstrate that alterations in neuronal complexity are a feature of both chronic migraine and chronic CRPS. However, each type of pain presents a unique cytoarchitectural signature, which may provide insight on how these pain states differentially transition from acute to chronic conditions.

Microstructural changes of basal ganglia in migraine with restless legs syndrome: findings from a neuroimaging study

In this study, it is planned to investigate the integrity of the basal ganglia structures in migraineurs with restless legs syndrome (RLS) to explore this relationship. In this study, 58 patients who were diagnosed migraine and 51 healthy controls (HCs) were included. Patients diagnosed with migraine were divided into two groups: Group I (migraine without RLS) and Group II (migraine with RLS). The integrity of basal ganglia was evaluated with region of interest diffusion tensor imaging method which allows us to assess microstructural changes of the tissue. The mean age of the patients was 35.98 ± 7.92 years, and the mean age of the HCs was 33.84 ± 11.06. 84.5% (n = 49) of the patients were female and 15.5% (n = 9) were male. 82.4% (n = 42) of the HCs were female, 17.6% (n = 9) were male. The number of  the patients without RLS was 41 (Group I), and the number of the patients with RLS was 17 (Group II). When basal ganglia structures were compared between groups of the patients with and without RLS, the fractional anisotropy (FA) value of the left putamen differed (Group I: 0.30 ± 0.06 vs. Group II: 0.25 ± 0.7, p = 0.01). The significant relationship was found attack frequency and presence of RLS with left putamen FA values according to multiple regression analysis. It was determined in this study that the changes in the microstructure of putamen, one of the basal ganglia structures, may be associated with the presence of RLS in migraineurs.

Investigating the Migraine Cycle over 21 Consecutive Days Using Proton Magnetic Resonance Spectroscopy and Resting-State fMRI: A Pilot Study

Recent neuroimaging studies have revealed important aspects of the underlying pathophysiological mechanisms of migraine suggesting abnormal brain energy metabolism and altered functional connectivity. Proton magnetic resonance spectroscopy (1H-MRS) studies investigated migraine patients in the interictal or ictal state. This first-of-its-kind study aimed to investigate the whole migraine cycle using 1H-MRS and resting-state functional magnetic resonance imaging (fMRI). A migraine patient underwent 1H-MRS and resting-state fMRI for 21 consecutive days, regardless of whether he was in an interictal or ictal state. Metabolite ratios were assessed and compared to the intrinsic connectivity of subcortical brain areas. Probable migraine phase-dependent changes in N-acetyl aspartate (NAA)/total creatine (tCr) and choline (Cho)/tCr levels are found in the left occipital lobe and left basal ganglia. NAA reflects neuronal integrity and Cho cellular membrane turnover. Such abnormalities may increase the susceptibility to excitatory migraine triggers. Functional connectivity between the right hippocampus and right or left pallidum was strongly correlated to the NAA/Cho ratio in the right thalamus, suggesting neurochemical modulation of these brain areas through thalamic connections. To draw statistically significant conclusions a larger cohort is needed.

Inter-individual differences in pain anticipation and pain perception in migraine: Neural correlates of migraine frequency and cortisol-to-dehydroepiandrosterone sulfate (DHEA-S) ratio

Previous studies targeting inter-individual differences in pain processing in migraine mainly focused on the perception of pain. Our main aim was to disentangle pain anticipation and perception using a classical fear conditioning task, and investigate how migraine frequency and pre-scan cortisol-to-dehydroepiandrosterone sulfate (DHEA-S) ratio as an index of neurobiological stress response would relate to neural activation in these two phases. Functional Magnetic Resonance Imaging (fMRI) data of 23 participants (18 females; mean age: 27.61± 5.36) with episodic migraine without aura were analysed. We found that migraine frequency was significantly associated with pain anticipation in brain regions comprising the midcingulate and caudate, whereas pre-scan cortisol-to DHEA-S ratio was related to pain perception in the pre-supplementary motor area (pre-SMA). Both results suggest exaggerated preparatory responses to pain or more general to stressors, which may contribute to the allostatic load caused by stressors and migraine attacks on the brain.

Altered brain structural topological properties and its correlations with clinical characteristics in episodic migraine without aura

PURPOSE

To investigate the topological alterations of the whole-brain white matter structural networks in episodic migraine (EM) without aura.

METHODS

Forty-five EM patients without aura and 35 age- and sex-matched healthy controls were registered, and underwent diffusion tensor MRI acquisition at interictal. Graph theory-based analyses were then performed for the characterization of brain structural network properties. Pearson correlation analysis was performed on each network metric between the EM patients and healthy controls.

RESULTS

The EM patients exhibited abnormal global network properties and local network topology that were characterized by more strongly integrated, more efficient, and faster information transferring. These network differences were widely located in the occipital, temporal, and parietal regions. Additionally, the local efficient of global parameters showed positive correlation with visual analogue scale, and along with prolonging disease duration, the nodal efficiency would be reduced, and the nodal shortest path length would be increased. Headache Impact Test version 6 scores have negative correlation with the nodal shortest path length, and positive correlations with the nodal efficiency.

CONCLUSION

The results indicate that EM patients had aberrant topological structure and make a better understanding of structural connectivity in EM; it may provide imaging evidence for clinical study of migraine pathogenesis.

Migraine Is More Than Just Headache: Is the Link to Chronic Fatigue and Mood Disorders Simply Due to Shared Biological Systems?

Migraine is a symptomatically heterogeneous condition, of which headache is just one manifestation. Migraine is a disorder of altered sensory thresholding, with hypersensitivity among sufferers to sensory input. Advances in functional neuroimaging have highlighted that several brain areas are involved even prior to pain onset. Clinically, patients can experience symptoms hours to days prior to migraine pain, which can warn of impending headache. These symptoms can include mood and cognitive change, fatigue, and neck discomfort. Some epidemiological studies have suggested that migraine is associated in a bidirectional fashion with other disorders, such as mood disorders and chronic fatigue, as well as with other pain conditions such as fibromyalgia. This review will focus on the literature surrounding alterations in fatigue, mood, and cognition in particular, in association with migraine, and the suggested links to disorders such as chronic fatigue syndrome and depression. We hypothesize that migraine should be considered a neural disorder of brain function, in which alterations in aminergic networks integrating the limbic system with the sensory and homeostatic systems occur early and persist after headache resolution and perhaps interictally. The associations with some of these other disorders may allude to the inherent sensory sensitivity of the migraine brain and shared neurobiology and neurotransmitter systems rather than true co-morbidity.

Migraine neuroscience: from experimental models to target therapy

Migraine sciences have witnessed tremendous advances in recent years. Pre-clinical and clinical experimental models have contributed significantly to provide useful insights into the brain structures that mediate migraine attacks. These models have contributed to elucidate the role of neurotransmission pathways and to identify the role of important molecules within the complex network involved in migraine pathogenesis. The contribution and efforts of several research groups from all over the world has ultimately lead to the generation of novel therapeutic approaches, specifically targeted for the prevention of migraine attacks, the monoclonal antibodies directed against calcitonin gene-related peptide or its receptor. These drugs have been validated in randomized placebo-controlled trials and are now ready to improve the lives of a large multitude of migraine sufferers. Others are in the pipeline and will soon be available.

Identifying neuroanatomical signatures in insomnia and migraine comorbidity

STUDY OBJECTIVES

While insomnia and migraine are often comorbid, the shared and distinct neuroanatomical substrates underlying these disorders and the brain structures associated with the comorbidity are unknown. We aimed to identify patterns of neuroanatomical substrate alterations associated with migraine and insomnia comorbidity.

METHODS

High-resolution T1-weighted images were acquired from subjects with insomnia, migraine, and comorbid migraine and insomnia, respectively, and healthy controls (HC). Direct group comparisons with HC followed by conjunction analyses identified shared regional gray matter volume (GMV) alterations between the disorders. To further examine large-scale anatomical network changes, a seed-based structural covariance network (SCN) analysis was applied. Conjunction analyses also identified common SCN alterations in two disease groups, and we further evaluated these shared regional and global neuroanatomical signatures in the comorbid group.

RESULTS

Compared with controls, patients with migraine and insomnia showed GMV changes in the cerebellum and the lingual, precentral, and postcentral gyri (PCG). The bilateral PCG were common GMV alteration sites in both groups, with decreased structural covariance integrity observed in the cerebellum. In patients with comorbid migraine and insomnia, shared regional GMV and global SCN changes were consistently observed. The GMV of the right PCG also correlated with sleep quality in these patients.

CONCLUSION

These findings highlight the specific role of the PCG in the shared pathophysiology of insomnia and migraine from a regional and global brain network perspective. These multilevel neuroanatomical changes could be used as potential image markers to decipher the comorbidity of the two disorders.

Ictal and interictal brain activation in episodic migraine: Neural basis for extent of allodynia

In some patients, migraine attacks are associated with symptoms of allodynia which can be localized (cephalic) or generalized (extracephalic). Using functional neuroimaging and cutaneous thermal stimulation, we aimed to investigate the differences in brain activation of patients with episodic migraine (n = 19) based on their allodynic status defined by changes between ictal and interictal pain tolerance threshold for each subject at the time of imaging. In this prospective imaging study, differences were found in brain activity between the ictal and interictal visits in the brainstem/pons, thalamus, insula, cerebellum and cingulate cortex. Significant differences were also observed in the pattern of activation along the trigeminal pathway to noxious heat stimuli in no allodynia vs. generalized allodynia in the thalamus and the trigeminal nucleus but there were no activation differences in the trigeminal ganglion. The functional magnetic resonance imaging (fMRI) findings provide direct evidence for the view that in migraine patients who are allodynic during the ictal phase of their attacks, the spinal trigeminal nucleus and posterior thalamus become hyper-responsive (sensitized)–to the extent that they mediate cephalic and extracephalic allodynia, respectively. In addition, descending analgesic systems seem as “switched off” in generalized allodynia.

Multimodal fusion analysis of structural connectivity and gray matter morphology in migraine

No specific migraine biomarkers have been found in single‐modality MRI studies. We aimed at establishing biomarkers for episodic and chronic migraine using diverse MRI modalities. We employed canonical correlation analysis and joint independent component analysis to find structural connectivity abnormalities that are related to gray matter morphometric alterations. The number of streamlines (trajectories of estimated fiber‐tracts from tractography) was employed as structural connectivity measure, while cortical curvature, thickness, surface area, and volume were used as gray matter parameters. These parameters were compared between 56 chronic and 54 episodic migraine patients, and 50 healthy controls. Cortical curvature alterations were associated with abnormalities in the streamline count in episodic migraine patients compared to controls, with higher curvature values in the frontal and temporal poles being related to a higher streamline count. Lower streamline count was found in migraine compared to controls in connections between cortical regions within each of the four lobes. Higher streamline count was found in migraine in connections between subcortical regions, the insula, and the cingulate and orbitofrontal cortex, and between the insula and the temporal region. The connections between the caudate nucleus and the orbitofrontal cortex presented worse connectivity in chronic compared to episodic migraine. The hippocampus was involved in connections with higher and lower number of streamlines in chronic migraine. Strengthening of structural networks involving pain processing and subcortical regions coexists in migraine with weakening of cortical networks within each lobe. The multimodal analysis offers a new insight about the association between brain structure and connectivity.

Dimensions of pain catastrophising and specific structural and functional alterations in patients with chronic pain: Evidence in medication-overuse headache

OBJECTIVES

We examined the neuroanatomical substrate of different pain catastrophising (PC) dimensions (i.e. rumination; magnification; helplessness) in patients with medication-overuse headache (MOH).

METHODS

We included 18 MOH patients who were administered the Pain Catastrophizing Scale (PCS) and scanned in a 3T-MRI. We conducted whole-brain volumetric and resting-state functional connectivity (FC) analysis to examine the association between grey matter (GM) density and FC strength and PCS dimensions controlling for depression and anxiety.

RESULTS

Higher total PCS score was associated with decreased GM density in precentral and inferior temporal gyrus, increased FC between middle temporal gyrus and cerebellum and reduced FC between precuneus and inferior temporal gyrus, as well as between frontal pole and temporal fusiform cortex. Regarding PCS dimensions, we mainly observed the involvement of (1) somatosensory cortex, supramarginal gyrus, basal ganglia, core default-mode network (DMN) in rumination; (2) somatosensory cortex, core DMN, dorsal medial prefrontal cortex (DMPFC)-DMN subsystem and cerebellum in magnification; and (3) temporal regions, DMN and basal ganglia in helplessness.

CONCLUSIONS

PC dimensions are associated with a specific structural and functional neuroanatomical pattern, which is different from the pattern observed when PC is considered as a single score. The involvement of basal ganglia and cerebellum needs further investigation.

Visually guided associative learning in pediatric and adult migraine without aura

INTRODUCTION

The Rutgers Acquired Equivalence Test is a visually guided equivalence learning paradigm that involves rule acquisition and generalization. Earlier we found impaired performance in this paradigm among adult migraine patients without aura. The aim of the study was to investigate if similar impairments can be found already in the pediatric form of the disease and to compare the performance of the pediatric study population with that of an adult study population. We hypothesized that the deficits observed in adults would be observable already in the pediatric population.

METHODS

Twenty-seven children and adolescents newly diagnosed with migraine without aura and 27 age- and sex-matched healthy controls were tested with the Rutgers Acquired Equivalence Test. Their performance data were compared to each other and those of an earlier adult study population involving 22 patients and 22 age- and sex-matched healthy controls. Four parameters characterizing performance in the two main phases of the paradigm were calculated for each of the four groups. Performance parameters were compared with Mann-Whitney U test.

RESULTS

In contrast to the decreased performance of the adult patients in the Rutgers Acquired Equivalence Test, no significant difference was found between pediatric patients and controls in any phase of the paradigm.

CONCLUSION

Children living with migraine without aura do not exhibit the same cognitive deficits in the Rutgers Acquired Equivalence Test as their adult counterparts. It can be hypothesized that the deficit of equivalence learning is not an inherent feature of the migrainous cognitive profile, rather the result of the interference of the disease with normal development.

Cortical and subcortical changes following sphenopalatine ganglion blocks in chronic migraine with medication overuse headache: a preliminary longitudinal study

Objective

The purpose of this pilot study was to investigate potential changes in brain morphology (cortical thickness and cortical/subcortical volume) accompanying a series of sphenopalatine ganglion (SPG) blockade treatments in chronic migraine with medication overuse headaches (CM^w/MOH).

Background

Local anesthetization of the SPG via intranasal application is used for the treatment for multiple types of headache disorders, including CM. Our previous longitudinal fMRI study revealed improved network connectivity after such treatment. However, the impact of SPG blocks on cortical, subcortical gray matter volume and cortical thickness has yet to be assessed.

Methods

Using magnetic resonance imaging (MRI), cortical/subcortical volume were measured in 12 chronic migraine patients before and after a series of 12 SPG blocks administered over a 6-week period (2 per week). The average time between MRI assessments was 6 weeks. Targeted, within-subjects t-tests comparing pre-treatment and post-treatment values in specific apriori brain regions of interest, including the hippocampus, amygdala, basal ganglia, somatosensory cortex, temporal cortex and occipital cortex, were used to estimate the impact of repetitive SPG blocks treatment on brain morphology in CM^w/MOH.

Results

Compared to baseline values, the number of moderate/severe headache days per month, HIT-6, PHQ-9 scores and allodynia scores were all significantly improved at the end of treatment. Analysis of MRI data revealed that the volume of the right hippocampus and the right palladium significantly decreased following SPG block treatment, while the volume of the left nucleus accumbens significantly increased following treatment. Cortical thickness in the left temporal pole and left lateral occipito-temporal gyrus significantly decreased following SPG block treatment.

Conclusion

Our results suggest SPG block treatment is associated with significant symptom improvement as well as significant structural brain changes in regions known to be associated with migraine and chronic pain processing in CM^w/MOH.

Modulation of brain networks by sumatriptan-naproxen in the inflammatory soup migraine model

Migraine is a debilitating condition; however, the pharmacological effects on central nervous system networks after successful therapy are poorly understood. Defining this neurocircuitry is critical to our understanding of the disorder and for the development of antimigraine drugs. Using an established inflammatory soup model of migraine-like pathophysiology (N = 12) compared with sham synthetic interstitial fluid migraine induction (N = 12), our aim was to evaluate changes in network-level functional connectivity after sumatriptan-naproxen infusion in awake, conscious rodents (Sprague-Dawley rats). Sumatriptan-naproxen infusion functional magnetic resonance imaging data were analyzed using an independent component analysis approach. Whole-brain analysis yielded significant between-group (inflammatory soup vs synthetic interstitial fluid) alterations in functional connectivity across the cerebellar, default mode, basal ganglia, autonomic, and salience networks. These results demonstrate the large-scale antimigraine effects of sumatriptan-naproxen co-administration after dural sensitization.

Brain Network Integration in Patients with Migraine: A Magnetoencephalography Study

Migraine is a common disorder with high social and medical impact. Patients with migraine have a much higher chance of experiencing headache attacks compared with the general population. Recent neuroimaging studies have confirmed that pathophysiology in the brain is not only limited to the moment of the attack but is also present in between attacks, the interictal phase. In this study, we hypothesized that the topology of functional brain networks is also different in the interictal state, compared with people who are not affected by migraine. We also expected that the level of network disturbances scales with the number of years people have suffered from migraine. Functional connectivity between 78 cortical brain regions was estimated for source-level magnetoencephalography data by calculating the phase lag index, in five frequency bands (delta-beta), and compared between healthy controls (n = 24) and patients who had been suffering from migraine for longer than 6 years (n = 12) or shorter than 6 years (n = 12). Moreover, the topology of the functional networks was characterized using the minimum spanning tree. The migraine groups did not differ from each other in functional connectivity. However, the network topology was different compared with healthy controls. The results were frequency specific, and higher average nodal betweenness centrality was specifically evident in higher frequency bands in patients with longer disease duration, while an opposite trend was present for lower frequencies. This study shows that patients with migraine have a different network topology in the resting state compared with healthy controls, whereby specific brain areas have altered topological roles in a frequency-specific manner. Some alterations appear specifically in patients with long-term migraine, which might show the long-term effects of the disease.

Structural neuroimaging findings in migraine patients with restless legs syndrome

PURPOSE

One out of three migraine patients might have accompanying restless legs syndrome (RLS). In our study, we aimed to compare the volumes of the brain structures of migraineurs with and without RLS.

METHODS

We had 37 female patients with migraine and 17 females as the control group. Nineteen migraineurs had no RLS (RLS₀) and 18 migraineurs had comorbidity of RLS (RLS₁). The volumes of the brain structures were obtained by manual measurements, volBrain, and voxel-based morphometry (VBM). Manually, we measured caudate and putamen volumes. We used age, years of education, depression, anxiety scores, and total intracranial volume as covariates.

RESULTS

According to VBM analyses, the volumes of the left superior occipital gyrus and precuneus were increased, and the substantia nigra and cuneus were decreased in the RLS₁ group compared with the RLS₀ group. RLS₁ patients had larger superior temporal gyrus, Brodmann area 38, and left insula, and RLS₀ patients had larger Brodmann area 22, right superior temporal gyrus, and Heschl gyrus compared with controls. Migraine and RLS₀ patients had a smaller corpus callosum anteriorly, whereas RLS₁ patients had a smaller splenium. Caudate volumes were larger in migraine patients via the three techniques. There was a positive relation between the caudate and putamen volumes and attack frequency.

CONCLUSIONS

Comorbidity of RLS might be a confounding factor in structural neuroimaging studies in migraine. Deficits in the visual network seem to be related to accompanying RLS; deficits in the auditory network are particularly related to migraine.

Neuroimaging investigation of memory changes in migraine: a systematic review

BACKGROUND

Individuals with migraine usually complain about lower memory performance. Diagnostic methods such as neuroimaging may help in the understanding of possible morphologic and functional changes related to the memory of those individuals. Therefore, the aim of this review is to analyze the available literature on neuroimaging changes related to memory processing in migraine.

METHODS

We searched the following databases: Pubmed/Medline, Psycinfo, Science Direct, Cochrane and Web of Science. We used articles without restriction of year of publication. The combination of descriptors used for this systematic review of literature were Neuroimaging OR Imaging OR Brain AND Migraine OR Chronic Migraine AND Memory.

RESULTS

Of the 306 articles found, nine were selected and all used magnetic resonance imaging (MRI). The studies used structural and functional MRI techniques with a predominance of 3 Tesla equipment and T1-weighted images. According to the results obtained reported by these studies, migraine would alter the activity of memory-related structures, such as the hippocampus, insula and frontal, parietal and temporal cortices, thereby suggesting a possible mechanism by which migraine would influence memory, especially in relation to the memory of pain.

CONCLUSIONS

Migraine is associated to global dysfunction of multisensory integration and memory processing. This condition changes the activity of structures in various regions related to memory of pain, prospective memory, as well as in short- and long-term verbal and visuospatial memories. However, it is necessary to perform studies with larger samples in association with cognitive tests, and without the interference of medications to verify possible alterations and to draw more concrete conclusions.

Fatal status migrainosus in Chiari 1 malformation

Background:

Headaches are common in Chiari Type 1 malformation (CM-1). The prevalence of migraine headaches in CM-1 is similar to that of the general population. However, when migraine headaches occur with CM-1, they tend to have an earlier age of onset, are more frequent and certainly more severe than when they occur without CM-1 association. The exact role or impact of CM-1 in migraine headaches has not been fully elucidated.

Case Description:

We report a fatal case of status migrainosus in 7 years old with CM-1 and review the literature on the possible associations.

Conclusion:

Migraines occurring in association with CM-1 pose a management challenge and can be potentially fatal especially if associated with autonomic symptoms. The exact pathophysiological interaction between these two conditions when they occur simultaneously needs to be further elucidated.

Cognition and Cognitive Impairment in Migraine

BACKGROUND

Migraine is a complex neurological disorder that affects a significant percentage of the human species, from all geographic areas and cultures. Cognitive symptoms and dysfunctions are interim and disabling components of this disorder and may be related to the brain processes underlying the pathophysiology. Yet they are often undervalued by clinicians. In this review, we present the different types of cognitive dysfunctions associated with migraine and the mechanisms that are potentially causing them.

FINDINGS

While reversible attack-related cognitive dysfunction seems extremely consistent and likely related to functional cortical and subcortical brain changes occurring during attacks, interictal cognitive dysfunction is less consistent and might become more relevant as attack frequency and disease complexity increase. Migraine traits do not seem a predisposition to long-term cognitive decline. Cognitive dysfunction is a frequent manifestation of migraine attacks and may be specific to this disorder; it is important to understand if it could be useful in migraine diagnosis. Attack-related cognitive dysfunction is clinically relevant and contributes to disability, so it should be perceived as a therapeutic target. While there is no evidence to support that migraine increases the risk of long-term or persistent cognitive dysfunction, the fact that it occurs during the attacks and may persist in subjects with frequent or complicated attacks should prompt the understanding of the mechanisms related to its pathophysiology for it may also clarify the processes underlying migraine.

Altered Vascular Permeability in Migraine-associated Brain Regions: Evaluation with Dynamic Contrast-enhanced MRI

Background Recent studies showed the possible association between inflammation-induced blood-brain barrier (BBB) structural changes followed by greater permeability of the BBB and chronic pain. Thus, measurement of BBB breakdown would be a valuable aid in the diagnosis in migraine. Dynamic contrast material-enhanced (DCE) MRI can determine perfusion and permeability properties related to the BBB. Purpose To evaluate the relationship between permeability of the BBB in migraine-associated brain regions by using DCE MRI. Materials and Methods In this prospective study, from September 2016 to December 2017, 56 study participants underwent DCE MRI after gadobutrol administration and were classified into migraine (n = 35) and healthy control (n = 21) groups. Automatic volumetric segmentation was performed on the pre-contrast-enhanced T1-weighted images by using FreeSurfer, and migraine-associated brain region masks were extracted by using the software NordicICE. The corresponding maps for pharmacokinetic parameters K^trans (the volume transfer constant) and V_p (the fractional plasma volume) were coregistered with the region-of-interest masks, and their mean values of corresponding total volume of interest were calculated. For comparison analyses, the Mann-Whitney tests were used. Receiver operating characteristic curve analysis and Spearman rank correlation tests were used to identify correlations between clinical characteristics and the aforementioned perfusion parameters. Results Mean age was younger in the migraine group (mean ± standard deviation, 57 years ± 12) than in the healthy control group (mean, 71 years ± 8) (P < .001). In the migraine group, the mean value of V_p in the left amygdala (median, 0.27 mL/100 g) was lower than that in the healthy control group (median, 0.39 mL/100 g) (P = .04). The mean value of V_p in the left amygdala was correlated with the intensity of headache attack in participants with migraine (correlation coefficient, -0.34; P = .04). Conclusion Lower fractional plasma volume in the left amygdala was observed in participants with migraine than in healthy participants. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Carroll and Ginat in this issue.

Endogenous Na+, K+-ATPase inhibitors and CSF [Na+] contribute to migraine formation

There is strong evidence that neuronal hyper-excitability underlies migraine, and may or may not be preceded by cortical spreading depression. However, the mechanisms for cortical spreading depression and/or migraine are not established. Previous studies reported that cerebrospinal fluid (CSF) [Na+] is higher during migraine, and that higher extracellular [Na+] leads to hyper-excitability. We raise the hypothesis that altered choroid plexus Na+, K+-ATPase activity can cause both migraine phenomena: inhibition raises CSF [K+] and initiates cortical spreading depression, while activation raises CSF [Na+] and causes migraine. In this study, we examined levels of specific Na+, K+-ATPase inhibitors, endogenous ouabain-like compounds (EOLC), in CSF from migraineurs and controls. CSF EOLC levels were significantly lower during ictal migraine (0.4 nM +/- 0.09) than from either controls (1.8 nM +/- 0.4) or interictal migraineurs (3.1 nM +/- 1.9). Blood plasma EOLC levels were higher in migraineurs than controls, but did not differ between ictal and interictal states. In a Sprague-Dawley rat model of nitroglycerin-triggered central sensitization, we changed the concentrations of EOLC and CSF sodium, and measured aversive mechanical threshold (von Frey hairs), trigeminal nucleus caudalis activation (cFos), and CSF [Na+] (ultra-high field 23Na MRI). Animals were sensitized by three independent treatments: intraperitoneal nitroglycerin, immunodepleting EOLC from cerebral ventricles, or cerebroventricular infusion of higher CSF [Na+]. Conversely, nitroglycerin-triggered sensitization was prevented by either vascular or cerebroventricular delivery of the specific Na+, K+-ATPase inhibitor, ouabain. These results affirm our hypothesis that higher CSF [Na+] is linked to human migraine and to a rodent migraine model, and demonstrate that EOLC regulates them both. Our data suggest that altered choroid plexus Na+, K+-ATPase activity is a common source of these changes, and may be the initiating mechanism in migraine.

Hypoechogenicity of brainstem raphe correlates with depression in migraine patients

Background

Brainstem raphe (BR) hypoechogenicity in transcranial sonography (TCS) has been depicted in patients with major depression (MD) and in depressed patients with different neurodegenerative diseases. But, up to date, the association of BR alterations in TCS with depression in migraineurs has never been reported. This study was to investigate the possible role of BR examination via TCS in migraineurs with depression.

Methods

Forty two migraine without aura (MwoA) patients and 40 healthy controls were recruited. Echogenicity of lentiform nuclei (LN), caudate nuclei (CN), substantia nigra (SN) and brainstem raphe (BR) and width of the frontal horns of the lateral ventricles and the third ventricle were assessed with TCS. The diagnosis of depression was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV (DSM –IV), and the severity of depression was measured by Hamilton Rating Scale for Depression (HAM-D) and Hospital Anxiety and Depression Scale depression subscale (HADS-D).

Results

There were no significant differences between migraineurs and controls in the width of frontal horn of the lateral ventricle (p = 0.955), width of third ventricle (p = 0.129) as well as in the echogenicity of SN (p = 0.942), CN (p = 0.053), LN (p = 0.052) and BR (p = 0.677). Here, it seems that more migraineurs were detected with increased echogenecity of CN and LN compared with controls (33.3% versus 15.0% for CN, 19.0% versus 5.0% for LN) though they had no statistical significance. Patients with hypoechogenic BR had significantly higher HAM-D and HADS-D scores than those with normal BR signal (p = 0.000 for both HAM-D and HADS-D), and most (83.33%) migraineurs with depression exhibited hypoechogenic raphe but none (0.00%) of the migraineurs without depression exhibited hypoechogenic raphe (p = 0.000).

Conlusions

TCS signal alteration of BR can be a biomarker for depression in migraine but it is not associated with migraine headache itself. LN and CN alterations in TCS may reflect a potential role of them in the pathogenesis of migraine, which needs to be further elucidated.

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.

Imaging of neuroinflammation in migraine with aura: A [11C]PBR28 PET/MRI study

OBJECTIVE

To determine if migraine with aura is associated with neuroinflammation, which has been suggested by preclinical models of cortical spreading depression (CSD) as well as imaging of human pain conditions.

METHODS

Thirteen migraineurs with aura and 16 healthy controls received integrated PET/MRI brain scans with [¹¹C]PBR28, a radioligand that binds to the 18 kDa translocator protein, a marker of glial activation. Standardized uptake value ratio (SUVR) was compared between groups, and regressed against clinical variables, using region of interest and whole-brain voxelwise analyses.

RESULTS

Compared to healthy controls, migraineurs demonstrated SUVR elevations in nociceptive processing areas (e.g., thalamus and primary/secondary somatosensory and insular cortices) as well as in areas previously shown to be involved in CSD generation (visual cortex). SUVR levels in frontoinsular cortex, primary/secondary somatosensory cortices, and basal ganglia were correlated with frequency of migraine attacks.

CONCLUSIONS

These findings demonstrate that migraine with aura is associated with neuroimmune activation/neuroinflammation, and support a possible link between CSD and glial activation, previously observed in animals.

Association between migraine frequency and neural response to emotional faces: An fMRI study

Previous studies have demonstrated that migraine is associated with enhanced perception and altered cerebral processing of sensory stimuli. More recently, it has been suggested that this sensory hypersensitivity might reflect a more general enhanced response to aversive emotional stimuli. Using functional magnetic resonance imaging and emotional face stimuli (fearful, happy and sad faces), we compared whole-brain activation between 41 migraine patients without aura in interictal period and 49 healthy controls. Migraine patients showed increased neural activation to fearful faces compared to neutral faces in the right middle frontal gyrus and frontal pole relative to healthy controls. We also found that higher attack frequency in migraine patients was related to increased activation mainly in the right primary somatosensory cortex (corresponding to the face area) to fearful expressions and in the right dorsal striatal regions to happy faces. In both analyses, activation differences remained significant after controlling for anxiety and depressive symptoms. These findings indicate that enhanced response to emotional stimuli might explain the migraine trigger effect of psychosocial stressors that gradually leads to increased somatosensory response to emotional clues and thus contributes to the progression or chronification of migraine.

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First fMRI study to explore neural response to emotional faces in migraine patients

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Migraine patients showed increased activation to fear in the right frontal regions

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Migraine frequency was related to enhanced activation to fearful and happy faces

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Activation in the right S1 and dorsal striatum was linked to migraine frequency

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Sensitivity to emotional stimuli might have a role in triggering migraine

Functional connectivity of hypothalamus in chronic migraine with medication overuse

OBJECTIVE

To investigate the functional connectivity of the hypothalamus in chronic migraine compared to interictal episodic migraine in order to improve our understanding of migraine chronification.

METHODS

Using task-free fMRI and ROI-to-ROI analysis, we compared anterior hypothalamus intrinsic connectivity with the spinal trigeminal nucleus in patients with chronic migraine (n = 25) to age- and sex-matched patients with episodic migraine in the interictal phase (n = 22). We also conducted a seed-to-voxel analysis with anterior hypothalamus as a seed.

RESULTS

All patients with chronic migraine had medication overuse. We found a significant connectivity (T = 2.08, p = 0.024) between anterior hypothalamus and spinal trigeminal nucleus in the chronic group, whereas these two regions were not connected in the episodic group. The strength of connectivity was not correlated with pain intensity (rho: 0.09, p = 0.655). In the seed-to-voxel analysis, three regions were more connected with the anterior hypothalamus in the chronic group: The spinal trigeminal nuclei (MNI coordinate x = 2, y = -44, z = -62), the right dorsal anterior insula (MNI coordinate x = 10, y = 10, z = 18), and the right caudate (MNI coordinate x = 12, y = 28, z = 6). However, these correlations were no longer significant after whole brain FWE correction.

CONCLUSION

An increased functional connectivity between the anterior hypothalamus and the spinal trigeminal nucleus, as previously reported in preictal episodic migraine, was demonstrated in chronic migraine with medication overuse. This finding confirms a major role of the anterior hypothalamus in migraine and suggests that chronic migraineurs are locked in the preictal phase.

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.

Brain systems at the intersection of chronic pain and self-regulation

Chronic pain is a multidimensional experience with cognitive, affective, and somatosensory components that can be modified by expectations and learning. Individual differences in cognitive and affective processing, as well as contextual aspects of the pain experience, render chronic pain an inherently personal experience. Such individual differences are supported by the heterogeneity of brain representations within and across chronic pain pathologies. In this review, we discuss the complexity of brain representations of pain, and, with respect to this complexity, identify common elements of network-level disruptions in chronic pain. Specifically, we identify prefrontal-limbic circuitry and the default mode network as key elements of functional disruption. We then discuss how these disrupted circuits can be targeted through self-regulation and related cognitive strategies to alleviate chronic pain. We conclude with a proposal for how to develop personalized multivariate models of pain representation in the brain and target them with real-time neurofeedback, so that patients can explore and practice self-regulatory techniques with maximal efficiency.

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.

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.

Volume and shape of subcortical grey matter structures related to headache: A cross-sectional population-based imaging study in the Nord-Trøndelag Health Study

BACKGROUND

The relationship between subcortical nuclei and headache is unclear. Most previous studies were conducted in small clinical migraine samples. In the present population-based MRI study, we hypothesized that headache sufferers exhibit reduced volume and deformation of the nucleus accumbens compared to non-sufferers. In addition, volume and deformation of the amygdala, caudate, hippocampus, pallidum, putamen and thalamus were examined.

METHODS

In all, 1006 participants (50-66 years) from the third Nord-Trøndelag Health Survey, were randomly selected to undergo a brain MRI at 1.5 T. Volume and shape of the subcortical nuclei from T1 weighted 3D scans were obtained in FreeSurfer and FSL. The association with questionnaire-based headache categories (migraine and tension-type headache included) was evaluated using analysis of covariance. Individuals not suffering from headache were used as controls. Age, sex, intracranial volume and Hospital Anxiety and Depression Scale were used as covariates.

RESULTS

No effect of headache status on accumbens volume and shape was present. Exploratory analyses showed significant but small differences in volume of caudate and putamen and in putamen shape between those with non-migrainous headache and the controls. A post hoc analysis showed that caudate volume was strongly associated with white matter hyperintensities.

CONCLUSION

We did not confirm our hypothesis that headache sufferers have smaller volume and different shape of the accumbens compared to non-sufferers. No or only small differences in volume and shape of subcortical nuclei between headache sufferers and non-sufferers appear to exist in the general population.

Heritability enrichment of specifically expressed genes identifies disease-relevant tissues and cell types

We introduce an approach to identify disease-relevant tissues and cell types by analyzing gene expression data together with genome-wide association study (GWAS) summary statistics. Our approach uses stratified linkage disequilibrium (LD) score regression to test whether disease heritability is enriched in regions surrounding genes with the highest specific expression in a given tissue. We applied our approach to gene expression data from several sources together with GWAS summary statistics for 48 diseases and traits (average N = 169,331) and found significant tissue-specific enrichments (false discovery rate (FDR) < 5%) for 34 traits. In our analysis of multiple tissues, we detected a broad range of enrichments that recapitulated known biology. In our brain-specific analysis, significant enrichments included an enrichment of inhibitory over excitatory neurons for bipolar disorder, and excitatory over inhibitory neurons for schizophrenia and body mass index. Our results demonstrate that our polygenic approach is a powerful way to leverage gene expression data for interpreting GWAS signals.

Responsivity of Periaqueductal Gray Connectivity Is Related to Headache Frequency in Episodic Migraine

Migraineurs show hypersensitivity to sensory stimuli at various stages throughout the migraine cycle. A number of putative processes have been implicated including a dysfunction in the descending pain modulatory system in which the periaqueductal gray (PAG) is considered to play a crucial role. Recurring migraine attacks could progressively perturb this system, lowering the threshold for future attacks, and contribute to disease chronification. Here, we investigated PAG connectivity with other brain regions during a noxious thermal stimulus to determine changes in migraineurs, and associations with migraine frequency. 21 episodic migraine patients and 22 matched controls were included in the study. During functional MRI, a thermode was placed on the subjects' temple delivering noxious and non-noxious heat stimuli. A psychophysiological interaction (PPI) analysis was carried out to examine pain-induced connectivity of the PAG with other brain regions. The PPI analysis showed increased PAG connectivity with the S1 face representation area and the supplementary motor area, an area involved with pain expectancy, in patients with higher frequency of migraine attacks. PAG connectivity with regions involved with the descending pain modulatory system (i.e., prefrontal cortex) was decreased in the migraineurs versus healthy individuals. Our results suggest that high frequency migraineurs may have diminished resistance to cephalic pain and a less efficient inhibitory pain modulatory response to external stressor (i.e., noxious heat). The findings support the notion that in migraine there is less effective pain modulation (viz., decreased pain inhibition or increased pain facilitation), potentially contributing to increased occurrence of attacks/chronification of migraine.