Article

Interictal Dysfunction of a Brainstem Descending Modulatory Center in Migraine Patients

PAIN Group, Brain Imaging Center, McLean Hospital, Harvard Medical School, Belmont, Massachusetts, United States of America.
PLoS ONE (Impact Factor: 3.53). 02/2008; 3(11):e3799. DOI: 10.1371/journal.pone.0003799
Source: PubMed

ABSTRACT The brainstem contains descending circuitry that can modulate nociceptive processing (neural signals associated with pain) in the dorsal horn of the spinal cord and the medullary dorsal horn. In migraineurs, abnormal brainstem function during attacks suggest that dysfunction of descending modulation may facilitate migraine attacks, either by reducing descending inhibition or increasing facilitation. To determine whether a brainstem dysfunction could play a role in facilitating migraine attacks, we measured brainstem function in migraineurs when they were not having an attack (i.e. the interictal phase).
Using fMRI (functional magnetic resonance imaging), we mapped brainstem activity to heat stimuli in 12 episodic migraine patients during the interictal phase. Separate scans were collected to measure responses to 41 degrees C and noxious heat (pain threshold+1 degrees C). Stimuli were either applied to the forehead on the affected side (as reported during an attack) or the dorsum of the hand. This was repeated in 12 age-gender-matched control subjects, and the side tested corresponded to that in the matched migraine patients. Nucleus cuneiformis (NCF), a component of brainstem pain modulatory circuits, appears to be hypofunctional in migraineurs. 3 out of the 4 thermal stimulus conditions showed significantly greater NCF activation in control subjects than the migraine patients.
Altered descending modulation has been postulated to contribute to migraine, leading to loss of inhibition or enhanced facilitation resulting in hyperexcitability of trigeminovascular neurons. NCF function could potentially serve as a diagnostic measure in migraine patients, even when not experiencing an attack. This has important implications for the evaluation of therapies for migraine.

1 Follower
 · 
164 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Discovery of the neuromuscular effects of botulinum toxin began in the early 19th century and has continued to evolve. Currently, onabotulinumtoxinA is approved by the U.S. Food and Drug Administration for two cosmetic and eight medical indications, including chronic migraine (CM). CM is a disabling form of migraine characterized by ≥15 headache days monthly and is believed to result from neuronal hypersensitivity to proinflammatory mediators, upregulation of sensory receptors, and consequent maladaptive pain responses with peripheral and central sensitization. OnabotulinumtoxinA achieves migraine prophylaxis in CM through regulation of vesicular trafficking and exocytosis, inhibition of peripheral release of neuropeptides and inflammatory peptides, and reduced cell surface expression of certain ion channels and receptors. Clinically, efficacy of onabotulinumtoxinA for CM has been shown in two phase III, placebo-controlled trials (PREEMPT 1 and PREEMPT 2). OnabotulinumtoxinA significantly reduced the number of headache days per 28-day cycle relative to placebo at week 24 (change from baseline: −8.4 days for onabotulinumtoxinA versus −6.6 days for placebo; P < 0.001, pooled data). OnabotulinumtoxinA improved health-related quality of life and had an acceptable safety profile. OnabotulinumtoxinA is the only approved treatment specifically for CM prevention and represents a safe and effective therapeutic for chronic migraineurs.
    Annals of the New York Academy of Sciences 08/2014; 1329(1). DOI:10.1111/nyas.12488 · 4.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Migraine is associated with derangements in perception of multiple sensory modalities including vision, hearing, smell, and somatosensation. Compared to people without migraine, migraineurs have lower discomfort thresholds in response to special sensory stimuli as well as to mechanical and thermal noxious stimuli. Likewise, the environmental triggers of migraine attacks, such as odors and flashing lights, highlight basal abnormalities in sensory processing and integration. These alterations in sensory processing and perception in migraineurs have been investigated via physiological studies and functional brain imaging studies. Investigations have demonstrated that migraineurs during and between migraine attacks have atypical stimulus-induced activations of brainstem, subcortical, and cortical regions that participate in sensory processing. A lack of normal habituation to repetitive stimuli during the interictal state and a tendency towards development of sensitization likely contribute to migraine-related alterations in sensory processing.
    Current Pain and Headache Reports 11/2014; 18(11):458. DOI:10.1007/s11916-014-0458-8 · 2.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Interregional cortical thickness correlations reflect underlying brain structural connectivity and functional connectivity. A few prior studies have shown that migraine is associated with atypical cortical brain structure and atypical functional connectivity amongst cortical regions that participate in sensory processing. However, the specific brain regions that most accurately differentiate the migraine brain from the healthy brain have yet to be determined. The aim of this study was to identify the brain regions that comprised interregional cortical thickness correlations that most differed between migraineurs and healthy controls. This was a cross-sectional brain magnetic resonance imaging (MRI) investigation of 64 adults with migraine and 39 healthy control subjects recruited from tertiary-care medical centers and their surrounding communities. All subjects underwent structural brain MRI imaging on a 3T scanner. Cortical thickness was determined for 70 brain regions that cover the cerebral cortex and cortical thickness correlations amongst these regions were calculated. Cortical thickness correlations that best differentiated groups of six migraineurs from controls and vice versa were identified. A model containing 15 interregional cortical thickness correlations differentiated groups of migraineurs from healthy controls with high accuracy. The right temporal pole was involved in 13 of the 15 interregional correlations while the right middle temporal cortex was involved in the other two. A model consisting of 15 interregional cortical thickness correlations accurately differentiates the brains of small groups of migraineurs from those of healthy controls. Correlations with the right temporal pole were highly represented in this classifier, suggesting that this region plays an important role in migraine pathophysiology.
    PLoS ONE 02/2015; 10(2):e0116687. DOI:10.1371/journal.pone.0116687 · 3.53 Impact Factor

Full-text (3 Sources)

Download
53 Downloads
Available from
Jun 4, 2014