Effects of OnabotulinumtoxinA on Allodynia and Interictal Burden of Patients with Chronic Migraine

BACKGROUND

We primarily aimed to ascertain whether treatment with OnabotulinumtoxinA (BoNTA) might influence the extent of the interictal burden and cutaneous allodynia in patients with chronic migraine (CM).

METHODS

Seventy CM patients, who received three consecutive cycles of BoNTA, were studied. The interictal burden was assessed with the Migraine Interictal Burden Scale (MIBS-4), while cutaneous allodynia was examined with the Allodynia Symptom Checklist (ASC-12) together with PI-NRS VAS to obtain hair brushing scores, and then these were compared from baseline (T0) to the last efficacy evaluation follow-up (T1). Efficacy outcomes, mostly mean headache days (MHD) and "Headache Impact Test" scores, were also assessed between T0 and T1.

RESULTS

BONTA improved the interictal burden, with a decrease in MIBS-4 scoring by an average of -7 at T1, compared to baseline (p < 0.001). The percentage of patients with a moderate/severe interictal burden was substantially decreased. Likewise, BoNTA reduced the extent of cutaneous allodynia, with a significant reduction in both the ASC-12 (1 vs. 6; p < 0.001) and PI-NRS VAS (1 vs. 5; p < 0.001) to hair brushing median scores at T1, compared to baseline. Reduced MHD rates were significantly associated with a smaller interictal burden at T1. The efficacy of BoNTA, with a significant reduction in MHD and HIT-6 scores at T1 compared to T0, was re-confirmed.

CONCLUSIONS

BoNTA resulted in a statistically significant reduction in the interictal burden and also improved cutaneous allodynia. The reduction in ictal burden was associated with the down-scaling of the interictal burden. Hence, BoNTA improved the full spectrum of migraine impairment by diminishing the clinical expression of central sensitization.

Roxadustat alleviates nitroglycerin-induced migraine in mice by regulating HIF-1α/NF-κB/inflammation pathway

Sensitization of central pain and inflammatory pathways play essential roles in migraine, a primary neurobiological headache disorder. Since hypoxia-inducible factor-1α (HIF-1α) is implicated in neuroprotection and inflammation inhibition, herein we investigated the role of HIF-1α in migraine. A chronic migraine model was established in mice by repeated injection of nitroglycerin (10 mg/kg, i.p.) every other day for 5 total injections. In the prevention and acute experiments, roxadustat, a HIF-1α stabilizer, was orally administered starting before or after nitroglycerin injection, respectively. Pressure application measurement, and tail flick and light-aversive behaviour tests were performed to determine the pressure pain threshold, thermal nociceptive sensitivity and migraine-related light sensitivity. At the end of experiments, mouse serum samples and brain tissues were collected for analyses. We showed that roxadustat administration significantly attenuated nitroglycerin-induced basal hypersensitivity and acute hyperalgesia by improving central sensitization. Roxadustat administration also decreased inflammatory cytokine levels in serum and trigeminal nucleus caudalis (TNC) through NF-κB pathway. Consistent with the in vivo results showing that roxadustat inhibited microglia activation, roxadustat (2, 10, and 20 μM) dose-dependently reduced ROS generation and inflammation in LPS-stimulated BV-2 cells, a mouse microglia cell line, by inhibiting HIF-1α/NF-κB pathway. Taken together, this study demonstrates that roxadustat administration ameliorates migraine-like behaviours and inhibits central pain sensitization in nitroglycerin-injected mice, which is mainly mediated by HIF-1α/NF-κB/inflammation pathway, suggesting the potential of HIF-1α activators as therapeutics for migraine.

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.

Brain Responses to Noxious Stimuli in Patients With Chronic Pain: A Systematic Review and Meta-analysis

IMPORTANCE

Functional neuroimaging is a valuable tool for understanding how patients with chronic pain respond to painful stimuli. However, past studies have reported heterogenous results, highlighting opportunities for a quantitative meta-analysis to integrate existing data and delineate consistent associations across studies.

OBJECTIVE

To identify differential brain responses to noxious stimuli in patients with chronic pain using functional magnetic resonance imaging (fMRI) while adhering to current best practices for neuroimaging meta-analyses.

DATA SOURCES

All fMRI experiments published from January 1, 1990, to May 28, 2019, were identified in a literature search of PubMed/MEDLINE, EMBASE, Web of Science, Cochrane Library, PsycINFO, and SCOPUS.

STUDY SELECTION

Experiments comparing brain responses to noxious stimuli in fMRI between patients and controls were selected if they reported whole-brain results, included at least 10 patients and 10 healthy control participants, and used adequate statistical thresholding (voxel-height P < .001 or cluster-corrected P < .05). Two independent reviewers evaluated titles and abstracts returned by the search. In total, 3682 abstracts were screened, and 1129 full-text articles were evaluated.

DATA EXTRACTION AND SYNTHESIS

Thirty-seven experiments from 29 articles met inclusion criteria for meta-analysis. Coordinates reporting significant activation differences between patients with chronic pain and healthy controls were extracted. These data were meta-analyzed using activation likelihood estimation. Data were analyzed from December 2019 to February 2020.

MAIN OUTCOMES AND MEASURES

A whole-brain meta-analysis evaluated whether reported differences in brain activation in response to noxious stimuli between patients and healthy controls were spatially convergent. Follow-up analyses examined the directionality of any differences. Finally, an exploratory (nonpreregistered) region-of-interest analysis examined differences within the pain network.

RESULTS

The 37 experiments from 29 unique articles included a total of 511 patients and 433 controls (944 participants). Whole-brain meta-analyses did not reveal significant differences between patients and controls in brain responses to noxious stimuli at the preregistered statistical threshold. However, exploratory analyses restricted to the pain network revealed aberrant activity in patients.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, preregistered, whole-brain analyses did not reveal aberrant fMRI activity in patients with chronic pain. Exploratory analyses suggested that subtle, spatially diffuse differences may exist within the pain network. Future work on chronic pain biomarkers may benefit from focus on this core set of pain-responsive areas.

Altered resting-state functional connectivity between subregions in the thalamus and cortex in migraine without aura

BACKGROUND AND PURPOSE

Migraine is a complex and disabling neurological disorder, the exact neurological mechanisms of which remain unclear. The thalamus is considered to be the hub of the central processing and integration of nociceptive information, as well as the modulation of these processes.

METHODS

A total of 48 migraineurs without aura (MWoAs) during the interictal phase and 48 age- and sex-matched healthy controls underwent resting-state functional magnetic resonance imaging scans. We utilized masked independent component analysis and seed-based functional connectivity (FC) to investigate whether MWoAs exhibited abnormal FC between subregions in the thalamus and the cortex regions.

RESULTS

The MWoAs showed significantly weaker FC between the anterior dorsal thalamic nucleus and left precuneus. Additionally, MWoAs exhibited significantly reduced FC between the ventral posterior nucleus (VPN) and left precuneus, right inferior parietal lobule (R-IPL) and right middle frontal gyrus. Furthermore, the FC Z-scores between the VPN and R-IPL were negatively correlated with pain intensity in MWoAs. The disease duration of patients was negatively correlated with the FC Z-scores between the VPN and R-IPL.

CONCLUSION

These altered thalamocortical connectivity patterns may contribute to multisensory integration abnormalities, deficits in pain attention, cognitive evaluation and pain modulation. Pain sensitivity and disease duration are closely tied to abnormal FC between the VPN and R-IPL. Remarkably, recurrent headache attacks might contribute to this maladaptive functional plasticity closely related to pain intensity.

Prophylactic Electroacupuncture on the Upper Cervical Segments Decreases Neuronal Discharges of the Trigeminocervical Complex in Migraine-Affected Rats: An in vivo Extracellular Electrophysiological Experiment

Purpose

This rat experiment aims to demonstrate the efficacy of electrical acupuncture in preventing migraine attacks by stimulating the acupoint GB20.

Introduction

Migraine, which takes 2ed at level four causes of GBD’s disease hierarchy, becomes a public health issue. It is important for physicians to supplement their knowledge of its treatment and consider alternative methods of therapy, such as acupuncture. However, the neurobiological and pathophysiological mechanisms of this prophylactic effect were unclear. The trigeminocervical complex is thought to be an important relay station in migraine pathophysiology as the key nuclei of the trigeminovascular system and the brainstem descending pain modulation system.

Methods

There were six groups involved in this study: control, model, electroacupuncture, non-acupoint electroacupuncture, saline+electroacupuncture and saline+non-acupoint electroacupuncture. We injected saline or inflammatory soup into dura mater to induce control or migraine in the rats. The mechanical pain threshold and the single-cell extraneural neurophysiology of the C1 spinal dorsal horn neurons in the trigeminocervical complex were detected.

Results

Pre-electroacupuncture could significantly increase the mechanical pain threshold of the periorbital region receptive field of the trigeminal nerve and decrease the discharges of neurons in the trigeminocervical complex. Acupuncture also reversed the abnormal skin pain response of the periorbital region receptive field of the trigeminal nerve caused by low-intensity stimulation.

Discussion

We believe that our study makes a significant contribution to the literature because it is the first of its kind to use GB20 to provide relief from migraine attacks and mechanical cephalic cutaneous hypersensitivity by regulating the neuronal discharge from trigeminocervical complex.

Migraine progression in subgroups of migraine based on comorbidities: Results of the CaMEO Study

Objective

To test the hypothesis that statistically defined subgroups of migraine (based on constellations of comorbidities and concomitant conditions; henceforth comorbidities), previously identified using Chronic Migraine Epidemiology and Outcomes (CaMEO) Study data, differ in prognosis, as measured by rates of progression from episodic migraine (EM) to chronic migraine (CM).

Methods

The onset of CM was assessed up to 4 times over 12 months in individuals with EM and ≥1 comorbidity at baseline, based on constellations of comorbidities (comorbidity classes). The “fewest comorbidities” class served as reference. Individuals completing ≥1 follow-up survey from the web-based CaMEO Study were included. Covariates included sociodemographic variables and headache characteristics. Sex, income, cutaneous allodynia, and medication overuse were modeled as binary variables; age, body mass index, headache-related disability (Migraine Disability Assessment [MIDAS]), and Migraine Symptom Severity Scale as continuous variables. CM onset was assessed using discrete time analysis.

Results

In the final sociodemographic model, all comorbidity classes had significantly elevated hazard ratios (HRs) for risk of progression to CM from EM, relative to fewest comorbidities. HRs for CM onset ranged from 5.34 (95% confidence interval [CI] 3.89–7.33; p ≤ 0.001) for most comorbidities to 1.53 (95% CI 1.17–2.01; p < 0.05) for the respiratory class. After adjusting for headache covariates independently, each comorbidity class significantly predicted CM onset, although HRs were attenuated.

Conclusions

Subgroups of migraine identified by comorbidity classes at cross-section predicted progression from EM (with ≥1 comorbidity at baseline) to CM. The relationship of comorbidity group to CM onset remained after adjusting for indicators of migraine severity, such as MIDAS.

Clinicaltrials.gov identifier

NCT01648530.

Effects of onabotulinumtoxinA treatment in patients with and without allodynia: results of the COMPEL study

Background

OnabotulinumtoxinA is effective in treating chronic migraine (CM), but there are limited data assessing how allodynia affects preventive treatment responses. This subanalysis of the 108-week, multicenter, open-label COMPEL Study assessed the efficacy and safety of onabotulinumtoxinA in people with CM with and without allodynia.

Methods

Patients (n = 715) were treated with onabotulinumtoxinA 155 U every 12 weeks for 9 treatment cycles. The Allodynia Symptom Checklist was used to identify patients with allodynia (scores ≥3). The primary outcome for this subanalysis was reduction in monthly headache days from baseline for weeks 105 to 108 in groups with and without allodynia. Other outcomes included assessments of moderate to severe headache days, disability (using the Migraine Disability Assessment [MIDAS] questionnaire), and health-related quality of life (Migraine-Specific Quality-of-Life Questionnaire [MSQ] v2). Adverse events and their relation to treatment were recorded.

Results

OnabotulinumtoxinA was associated with a significant mean (SD) reduction in headache day frequency at week 108 relative to baseline in patients with (n = 289) and without (n = 426) allodynia (− 10.8 [7.1] and − 12.5 [7.4], respectively; both P < 0.001) that was significantly greater in patients without allodynia (P = 0.044 between-subgroup comparison). Moderate to severe headache days were significantly reduced at week 108 in patients with and without allodynia (− 9.6 [6.9] and − 10.5 [7.2]; both P < 0.001); reduction was similar between groups. MIDAS scores improved significantly at week 108 (− 53.0 [50.3] and − 37.7 [53.0]; both P < 0.001), with a significant between-group difference in favor of those with allodynia (P = 0.005). Similarly, MSQ subscale scores (Role Function Preventive, Role Function Restrictive, Emotional Function) significantly improved at week 108 for patients with and without allodynia: 20.6 (21.9) and 16.9 (20.7), 28.0 (23.3) and 24.7 (22.7), and 27.6 (26.5) and 24.9 (26.1), respectively (all P < 0.001). OnabotulinumtoxinA was well tolerated in patients with and without allodynia.

Conclusion

Results indicate that onabotulinumtoxinA is associated with reductions from baseline in multiple efficacy outcomes for up to 108 weeks whether or not allodynia is present. The allodynia group showed a smaller treatment response for reduction in headache days, but a similar or greater treatment response for improvement in other measures. No new safety concerns were identified.

Electronic supplementary material

The online version of this article (10.1186/s10194-018-0952-1) contains supplementary material, which is available to authorized users.

Non-headache symptoms in migraine patients

Migraine is one of the most common neurological disorders. In addition to severe headaches, non-headache symptoms associated with migraine attacks as well as co-morbid disorders frequently aggravate the disabling of migraine patients. Some of these symptoms are related to poor outcomes. In this review, we update the advances of studies on certain non-headache symptoms, including visual disturbance, gastrointestinal symptoms, allodynia, vestibular symptoms, and symptoms of co-morbid restless legs syndrome and psychiatric disorders.

[Abdominal pain in migraine patients]

AIM

To study the frequency of comorbid abdominal pain in migraine patients and the influence of that symptom on the formation of disease phenotype.

MATERIAL AND METHODS

Clinical features of migraine were studied in 66 patients with episodic migraine and 40 patients with chronic migraine. Presence of pain, intensity, duration of seizure-associated abdominal pain and interictal abdominal pain were assessed.

RESULTS AND CONCLUSION

The frequency of abdominal pain in the painful phase of migraine was >11% and did not depend on the type of migraine. Pain in the abdomen were reported by 88% of patients, with the increase in the frequency in patients with chronic migraine. The intensity and frequency of abdominal pain did not depend on organic pathology of the digestive system. Correlations between the intensity and duration of abdominal pain during the migraine attack phase (k=0.59), between the intensity of associated pain and maladjustment severity (k=0.59), and also between the abdominal pain intensity during the painful phase and in the interictal period were identified. Allodynia developed more frequently in patients with abdominal pain between migraine attacks (РF=0.005). Also relationships between the level of intensity of interictal abdominal pain and the rates of alexithymia (k=0.24), anxiety (k=0.29) and depression (k=0.25) were revealed. The association of abdominal pain with disease severity and allodynia suggests similar development of these symptoms.

Central Sensitization-Based Classification for Temporomandibular Disorders: A Pathogenetic Hypothesis

Dysregulation of Autonomic Nervous System (ANS) and central pain pathways in temporomandibular disorders (TMD) is a growing evidence. Authors include some forms of TMD among central sensitization syndromes (CSS), a group of pathologies characterized by central morphofunctional alterations. Central Sensitization Inventory (CSI) is useful for clinical diagnosis. Clinical examination and CSI cannot identify the central site(s) affected in these diseases. Ultralow frequency transcutaneous electrical nerve stimulation (ULFTENS) is extensively used in TMD and in dental clinical practice, because of its effects on descending pain modulation pathways. The Diagnostic Criteria for TMD (DC/TMD) are the most accurate tool for diagnosis and classification of TMD. However, it includes CSI to investigate central aspects of TMD. Preliminary data on sensory ULFTENS show it is a reliable tool for the study of central and autonomic pathways in TMD. An alternative classification based on the presence of Central Sensitization and on individual response to sensory ULFTENS is proposed. TMD may be classified into 4 groups: (a) TMD with Central Sensitization ULFTENS Responders; (b) TMD with Central Sensitization ULFTENS Nonresponders; (c) TMD without Central Sensitization ULFTENS Responders; (d) TMD without Central Sensitization ULFTENS Nonresponders. This pathogenic classification of TMD may help to differentiate therapy and aetiology.

Grey matter alterations in migraine: A systematic review and meta-analysis

Objectives

To summarize and meta-analyze studies on changes in grey matter (GM) in patients with migraine. We aimed to determine whether there are concordant structural changes in the foci, whether structural changes are concordant with functional changes, and provide further understanding of the anatomy and biology of migraine.

Methods

We searched PubMed and Embase for relevant articles published between January 1985 and November 2015, and examined the references within relevant primary articles. Following exclusion of unsuitable studies, meta-analysis were performed using activation likelihood estimation (ALE).

Results

Eight clinical studies were analyzed for structural changes, containing a total of 390 subjects (191 patients and 199 controls). Five functional studies were enrolled, containing 93 patients and 96 controls. ALE showed that the migraineurs had concordant decreases in the GM volume (GMV) in the bilateral inferior frontal gyri, the right precentral gyrus, the left middle frontal gyrus and the left cingulate gyrus. GMV decreases in right claustrum, left cingulated gyrus, right anterior cingulate, amygdala and left parahippocampal gyrus are related to estimated frequency of headache attack. Activation was found in the somatosensory, cingulate, limbic lobe, basal ganglia and midbrain in migraine patients.

Conclusion

GM changes in migraineurs may indicate the mechanism of pain processing and associated symptoms. Changes in the frontal gyrus may predispose a person to pain conditions. The limbic regions may be accumulated damage due to the repetitive occurrence of pain-related processes. Increased activation in precentral gyrus and cingulate opposed to GMV decrease might suggest increased effort duo to disorganization of these areas and/or the use of compensatory strategies involving pain processing in migraine. Knowledge of these structural and functional changes may be useful for monitoring disease progression as well as for therapeutic interventions.

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There are some concordant structural changes in migraine.

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Some structural changes like frontal lobe and cingulate are also over-activated in interictal phase.

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Frontal gyrus may predispose a person to pain condition.

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Limbic regions may be accumulating brain damage due to pain-related processes.

Structural alterations of the brainstem in migraine

Atypical brainstem modulation of pain might contribute to changes in sensory processing typical of migraine. The study objective was to investigate whether migraine is associated with brainstem structural alterations that correlate with this altered pain processing.

MRI T1-weighted images of 55 migraine patients and 58 healthy controls were used to: (1) create deformable mesh models of the brainstem that allow for shape analyses; (2) calculate volumes of the midbrain, pons, medulla and the superior cerebellar peduncles; (3) interrogate correlations between regional brainstem volumes, cutaneous heat pain thresholds, and allodynia symptoms.

Migraineurs had smaller midbrain volumes (healthy controls = 61.28 mm³, SD = 5.89; migraineurs = 58.80 mm³, SD = 6.64; p = 0.038), and significant (p < 0.05) inward deformations in the ventral midbrain and pons, and outward deformations in the lateral medulla and dorsolateral pons relative to healthy controls. Migraineurs had a negative correlation between ASC-12 allodynia symptom severity with midbrain volume (r = − 0.32; p = 0.019) and a positive correlation between cutaneous heat pain thresholds with medulla (r = 0.337; p = 0.012) and cerebellar peduncle volumes (r = 0.435; p = 0.001).

Migraineurs with greater symptoms of allodynia have smaller midbrain volumes and migraineurs with lower heat pain thresholds have smaller medulla and cerebellar peduncles. The brainstem likely plays a role in altered sensory processing in migraine and brainstem structure might reflect severity of allodynia and hypersensitivity to pain in migraine.

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Migraineurs have less volume in midbrain regions and show morphologic shape indentations in ventral pons and midbrain as well as right and left outward deformations in the lateral aspects of the pons and medulla.

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Migraineurs with more severe allodynia have less midbrain volume and migraineurs with lower heat pain thresholds have less volume in the cerebellar peduncles and medulla.

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Brainstem morphological alterations might reflect dysfunctional pain modulation in migraine.

Functional interictal changes of pain processing in migraine with ictal cutaneous allodynia

Objective

A prospective clinical imaging study has been conducted to investigate pain processing functional pathways during trigeminal heat stimulation (THS) in patients with migraine without aura experiencing ictal cutaneous allodynia (CA) (MwoA CA+).

Methods

Using whole-brain BOLD-fMRI, functional response to THS at three different intensities (41°, 51° and 53℃) was investigated interictally in 20 adult MwoA CA+ patients compared with 20 MwoA patients without ictal CA (MwoA CA−) and 20 healthy controls (HCs). Secondary analyses evaluated associations between BOLD signal change and clinical features of migraine.

Results

During moderate-noxious THS (51℃), we observed a significantly greater activation in (a) the anterior cingulate cortex in MwoA CA+ patients compared to HCs and (b) the middle frontal gyrus in MwoA CA+ patients compared to both MwoA CA− patients and HCs. Furthermore, during high-noxious THS (53℃) a significantly decreased activation in the secondary somatosensory cortices was observed in (a) MwoA CA− patients compared to both MwoA CA+ patients and HCs and (b) MwoA CA+ patients compared to HCs. CA severity was positively correlated with the secondary somatosensory cortices activation.

Conclusions

Our findings suggest that CA may be subtended by both a dysfunctional analgesic compensatory mechanism and an abnormal internal representation of pain in migraine patients.

What Do We Know About the Pathophysiology of Chronic Pain? Implications for Treatment Considerations

We discuss the complex features of the pathophysiology of chronic pain and the implications for treatment and provide an overview of nociceptive processes, neuropathic pain, cold hyperalgesia, peripheral nerve injury, wind-up pain, central sensitization, and common clinical presentation and diagnostic criteria. Advanced medicine has proven that chronic pain need not involve any structural pathology as pain is a complex biopsychosocial experience. Treatment of the specific mechanisms responsible for pain should be aimed at preventing and or reducing dysfunctional neuro-plasticity resulting from poorly controlled chronic pain. Further study is needed to reduce the probability and of persistent changes that cause chronic pain.

Central Nervous System Underpinnings of Sensory Hypersensitivity in Migraine: Insights from Neuroimaging and Electrophysiological Studies

Whereas considerable data have been generated about the pathophysiology of pain processing during migraine attacks, relatively little is known about the neural basis of sensory hypersensitivity. In migraine, the term "hypersensitivity" encompasses different and probably distinct pathophysiological aspects of sensory sensitivity. During attacks, many patients have enhanced sensitivity to visual, auditory and/or olfactory stimuli, which can enhance headache while interictally, migraineurs often report abnormal sensitivity to environmental stimuli that can cause nonpainful discomfort. In addition, sensorial stimuli can influence and trigger the onset of migraine attacks. The pathophysiological mechanisms and the origin of such sensitivity (individual predisposition to develop migraine disease or consequence of repeated migraine attacks) are ill understood. Functional neuroimaging and electrophysiological studies allow for noninvasive measures of neuronal responses to external stimuli and have contributed to our understanding of mechanisms underlying sensory hypersensitivity in migraine. The purpose of this review is to present pivotal neuroimaging and neurophysiological studies that explored the basal state of brain responsiveness to sensory stimuli in migraineurs, the alterations in habituation and attention to sensory inputs, the fluctuations of responsiveness to sensory stimuli before and during migraine attacks, and the relations between sensory hypersensitivity and clinical sensory complaints.