How migraine makes waves

Health professionals have long thought that dehydration triggers migraine. The previous theory was that lack of fluid caused the blood to thicken, prompting the brain’s blood vessels to dilate, thereby increasing the flow of blood and oxygen; however, scientific research has since overturned this theory.

Many neurologists now believe that the excessive thirst that some migraine sufferers report in the days or hours before an episode is part of the cluster of warning signs that precede a migraine.

“Over the past decade or so, evidence has indicated that migraine aura is due to changes in the function of nerve cells in the brain,” says Dr Jon Simcock, a neurologist and medical adviser for the Neurological Foundation of New Zealand. “These changes cause the nerve cells to become overexcited and overreact, and this triggers migraine symptoms such as flashing lights.”

This excitation spreads like a wave over the brain areas that are involved with functions such as vision. “After overworking those brain cells, this electrical wave then leaves a ‘blank spot’ — an  area of depressed function where the same cells underperform for a while,” explains Simcock.

“In contrast, neurologists now think that migraine itself results from an irritation of the nerve cells in the walls of the brain’s arteries. This irritation causes inflammation that leads to intense head pain. However, we still don’t completely understand how or why migraine triggers provoke this irritation.”
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