Cerebro-Cerebellar Networks in Migraine Symptoms and Headache

Exploring vestibulocerebellum-vestibular nuclei-spinal trigeminal nucleus causals communication and TRPV2 ion channel in a mouse model of vestibular migraine

BACKGROUND

Vestibular migraine (VM) is a disorder characterized by recurrent episodes of dizziness or vertigo and is often accompanied by headache. The mechanisms underlying vestibular dysfunction and pain in VM remain unclear.

METHODS

Chronic migraine (CM) and VM models were induced by NTG and kainic acid, respectively. Behavioral assessments were conducted to evaluate vestibular dysfunction and pain in the VM and CM models. Transmission electron microscopy (TEM) was used to examine peripheral receptor impairment. Immunofluorescence, including staining for Cellular Proto-oncogene (c-Fos), Neuronal Nuclei (NeuN), and calcitonin gene-related peptide (CGRP), identified activated brain regions such as the cortex, midbrain, and cerebellum. Multiplex immunohistochemistry and cholera toxin subunit B (CTB) tracing were performed to analyze nuclear heterogeneity and neural communication. Additionally, RNA sequencing (RNA-Seq) and Ionized calcium-binding adapter molecule 1 (IBA1) immunostaining were used to investigate ion channel expression in the spinal trigeminal nucleus caudalis (Sp5c).

RESULTS

CM and VM-related behaviors, such as allodynia and balance disturbance, were successfully reproduced in mouse model. TEM revealed significant damage to peripheral sensory receptors, particularly in the trigeminal ganglion and cochlear cells. Distinct activation patterns of c-Fos and CGRP were observed in VMs and CMs. CTB tracing confirmed that signals are transmitted from the vestibulocerebellum (VbC) to the Sp5c via the vestibular nuclei (VN). Furthermore, RNA-Seq combined with coimmunostaining revealed an increased expression of transient receptor potential vanilloid 2 (TRPV2) ion channels in microglia within Sp5c, indicating their potential role in VM pathology.

CONCLUSIONS

This study preliminarily explored VbC-VN-Sp5c communication and identified TRPV2 ion channels in microglia as key players in neuron-glia crosstalk in VM. These findings provide new insights into the mechanisms underlying vestibular migraine and suggest potential therapeutic targets.

Abnormal Functional Network Centrality and Causal Connectivity in Migraine Without Aura: A Resting-State fMRI Study

OBJECTIVE

The pathophysiological mechanism of migraine is still not clear. Thus, this study aimed to evaluate the changes in effective connectivity (EC) in the brain functional network underlying migraine and its association with clinical measures of migraine.

BACKGROUND

Fifty patients with episodic migraine without aura (MwoA) and 48 healthy controls (HCs) were enrolled in this study. Spontaneous activity in the brain was evaluated using the degree centrality (DC) method, and the brain regions with obvious signal differences between the two groups were taken as seed points for whole brain Granger causality analysis (GCA) analysis. The values of the brain regions with differences in DC and GCA were extracted and correlated with clinical measures of migraine.

RESULTS

Compared to the HCs, the MwoA patients showed decreased DC in the left inferior temporal gyrus (ITG) and increased DC in the right precuneus and exhibited significantly decreased EC from the left ITG to the left inferior parietal gyrus and right inferior occipital gyrus (IOG) as well as significantly increased EC from the left postcentral gyrus and left cerebellum posterior lobe to the left ITG. Moreover, decreased EC from the left thalamus to the right precuneus was found in the MwoA patients compared to the HCs. The DC values in the right precuneus were significantly negatively correlated with the duration of headache. Additionally, we found a significantly positive correlation between the Migraine Disability Assessment questionnaire score and the EC from the left ITG to the right IOG, as well as between the intensity of headache and the EC from the left thalamus to the right precuneus.

CONCLUSIONS

This study found changes in the EC of the brain functional network underlying migraine and their associations with migraine-related parameters. These findings are helpful for understanding the pathophysiological mechanism in migraine patients.

Deep brain stimulation for chronic refractory cluster headache: A case series about long-term outcomes and connectivity analysis

OBJECTIVE

The aim of this study was to provide long-term clinical results-including "sweet spot" identification and connectomic imaging analysis-in a series of patients treated with deep brain stimulation for refractory chronic cluster headache.

BACKGROUND

Deep brain stimulation is a relatively recent indication for the treatment of refractory chronic cluster headache. This indication has generated substantial debate in recent years due to uncertainty surrounding the mechanism of action and the lack of long-term efficacy data.

METHODS

Case retrospective series of adult patients diagnosed with refractory chronic cluster headache and treated with deep brain stimulation. Demographic and clinical data were registered preoperatively and at 3, 6, 12, and 24 months. The primary endpoint was reduction in headache load, a composite score of frequency, severity, and duration of each attack. Imaging analyses (sweet spot and connectomic analyses) were performed to identify the brain regions most closely correlated with the reduction in headache load and to identify the structural networks involved. Treatment response was categorized according to the reduction in headache load, as follows: poor (<30% reduction), partial (30-50%), or high (>50%).

RESULTS

A total of 14 patients were included, with a mean (standard deviation [SD]) age of 42.4 (10.7) years and mean (SD) headache duration of 8.0 (5.8) years. Headache load scores decreased significantly from baseline to Month 24: mean (SD) 424.2 (325.9) versus 135.9 (155.7) (p = 0.001). In most patients (eight patients [58.0%]), headache load scores decreased by 50% after treatment. The other six patients showed either a partial (three [21.0%]) or poor (three [21.0%]) response. The optimized sweet spot was the lateral ventral tegmental area ((Montreal Neurological Institute) MNI coordinates of the center of mass: x = ± 9.0 mm, y = -10.6 mm, z = -3.5 mm). The connectomic analysis pointed to the probable implication of corticorubral tracts.

CONCLUSION

These findings suggest that a substantial proportion of patients with refractory chronic cluster headache obtain significant long-term clinical benefits from deep brain stimulation. Good responders were characterized by a robust improvement in headache load within 3-6 months after surgery. The lateral ventral tegmental area was identified as the best target for this indication, with the likely participation of corticorubral tracts.

Differences in Static and Dynamic Resting-State Functional Connectivity between Migraineurs with and without Photophobia, without Phonophobia or Osmophobia

BACKGROUND

We have previously shown that static and dynamic resting-state functional connectivity differ between migraineurs with and without photophobia, phonophobia, or osmophobia. Furthermore, some patients with photophobia also experience phonophobia or osmophobia. To investigate the functional connectivity specific to migraineurs with photophobia, we examined the differences in static and dynamic resting-state functional connectivity between patients with and without photophobia, with no phonophobia or osmophobia.

METHODS

Fifteen migraineurs with photophobia but without phonophobia or osmophobia, as well as 15 sex- and age-matched migraineurs without photophobia, phonophobia, or osmophobia, underwent 3-T functional magnetic resonance imaging during the interictal phase. Static and dynamic resting-state functional connectivity were compared using region-of-interest analyses of 91 cortical, 15 subcortical, and 26 cerebellar areas.

RESULTS

Static resting-state functional connectivity analysis revealed ten significant connectivity pairs in patients with photophobia, while dynamic resting-state functional connectivity analysis revealed six significant connectivity pairs in patients with photophobia. Migraineurs with photophobia had significantly lower connectivity between the cerebellar hemisphere and the temporal region than those without photophobia in both static and dynamic studies.

CONCLUSIONS

Our results show that lower resting-state functional connectivity between the cerebellar hemisphere and the temporal region is specific to migraineurs with photophobia.

Vestibular migraine: an update

PURPOSE OF REVIEW

We performed a narrative review of the recent findings in epidemiology, clinical presentation, mechanisms and treatment of vestibular migraine.

RECENT FINDINGS

Vestibular migraine is an underdiagnosed condition that has a high prevalence among general, headache and neuro-otology clinics. Vestibular migraine has a bimodal presentation probably associated with a hormonal component in women. These patients could have a complex clinical phenotype including concomitant autonomic, inflammatory or connective tissue conditions that have a higher prevalence of psychological symptoms, which may mistakenly lead to a diagnosis of a functional neurological disorder. A high proportion of patients with postural perceptual persistent dizziness have a migraine phenotype. Independently of the clinical presentation and past medical history, patients with the vestibular migraine phenotype can respond to regular migraine preventive treatments, including those targeting the calcitonin gene-related peptide pathways.

SUMMARY

Vestibular migraine is an underdiagnosed migraine phenotype that shares the pathophysiological mechanisms of migraine, with growing interest in recent years. A thorough anamnesis is essential to increase sensitivity in patients with unknown cause of dizziness and migraine treatment should be considered (see supplemental video-abstract).

Current Knowledge about Headaches Attributed to Ischemic Stroke: Changes from Structure to Function

Headaches are common after ischemic stroke (IS). Unlike primary headaches, headaches attributed to IS have specific clinical features. This review describes the epidemiology, clinical characteristics, risk factors, and influence of IS headaches. Previous reports were summarized to show the correlations between headaches and structural lesions in the cerebral cortex, subcortical white matter, deep gray matter nuclei, brainstem, and cerebellum. However, the substantial heterogeneity of IS, subjective evaluations of headaches, and inadequate cohort studies make it difficult to explore the pathophysiology of headaches attributed to IS. In our recommendation, favorable imaging techniques, such as magnetic resonance imaging and positron emission tomography, may provide new insights into mechanical studies of IS headaches from structure to function. It may also be helpful to extend the research field by targeting several shared signal transducers between headaches and IS. These markers might be neuropeptides, vasoactive substances, ion channels, or electrophysiologic changes.