How do brain activities change during migraines?

How do brain activities change during migraines?

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Brain activity in migraine aura examined

Migraines are not only characterized by headaches, but are also accompanied by so-called aura symptoms in some of those affected. So far, what mechanisms in the brain trigger these symptoms has remained largely unclear. Scientists from the Danish Headache Center, the Neurology of the University of Copenhagen and the University Eye Clinic Magdeburg have now analyzed brain activity in patients with a migraine aura and discovered striking patterns.

The migraine aura manifests itself, for example, in the form of visual disturbances, which can be of different types and range from the perception of flickering lightning to loss of visual field, reports the University Medical Center Magdeburg. However, the underlying mechanisms of aura symptoms have so far largely remained unclear. In the current study, the scientists have now examined the brain activity of migraine patients with the aid of magnetic resonance imaging (magnetic resonance imaging; MRI) and identified conspicuous patterns. Their results were published in the specialist magazine "Annals of Neurology".

Migraine aura affects around a third of patients

Migraines are primarily known for recurring violent headaches, but there may also be other complaints, which are summarized under the term migraine aura. "Around ten percent of the total population suffers from migraine attacks and a third of them experience the so-called migraine aura," according to the Magdeburg University Hospital. This is manifested, for example, by visual disturbances. The underlying mechanisms have so far not been well understood.

Magnetic resonance imaging to measure brain activity

The investigation by means of magnetic resonance imaging allows not only the assessment of the brain anatomy, but also the brain activity and so this method could represent an access to the neuronal mechanisms of the visual symptoms, the scientists justify their research approach. However, because of the unpredictable short-lived nature of the aura, it is very difficult to conduct systematic studies in patients during an aura. So far, there has actually been only one examination in which the aura of a patient was analyzed in detail using MRI scans. The study found signal changes in the brain that were consistent with the aura properties. "However, this has so far not been repeated or confirmed," the researchers report.

Patients examined during aura attacks

So many questions about the pathophysiology of the aura and its relationship to migraines remain unanswered. The current study by the international team of researchers started here to contribute to a better understanding of the migraine aura. "Using functional magnetic resonance imaging (fMRI), they examined five patients during aura attacks," reports the Magdeburg University Hospital. The aura was specifically triggered by inhalation of air with reduced oxygen, atmospheric air or through sports combined with light stimulation. "As soon as the patients reported the appearance and progression of visual disturbances, they were immediately examined in an MRI scanner," the scientists explain. The researchers measured the brain's visual cortex responses to moving checkerboard patterns.

Functional changes in the brain are noticeable

The scientists found that different aura symptoms reflect different functional changes in the brain, for example, patients with visual aura symptoms such as visual field loss, decreased responses in the visual cortex, while patients who saw flashes of light and flicker showed enlarged responses. If both halves of the visual field were affected by the visual symptoms, "the changes in the activity of the visual cortex were also observed in both hemispheres"; the researchers explain further. This was the proof that different aura symptoms are related to different responses from the visual cortex. This represents an important step towards a better understanding of the migraine aura and gives hope for new approaches for effective treatment, the scientists conclude. (fp)

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Video: Headache or Migraine? (August 2022).