Hadjikhani and her colleagues had previously found changes in the brain's white matter (which consists of nerve fibers) in people suffering from migraines.
"We found changes in migraineurs compared to controls in the white matter pathways that are important for the somatosensory processing of pain," she explained. "That's why we decided to look at cortical thickness, to see if white matter had any bearings on the gray matter [which consists of cell bodies]."
The somatosensory system includes sensations from the body -- including touch, pain and pressure -- that do not involve the organs devoted to sense, such as the eyes and ears.
The researchers used brain scanning to examine 24 people with migraine, 12 with aura and 12 without. They then compared those scans to scans of 12 people without migraine.
The cortical thickness of the somatosensory cortex area (SSC) of the brain was an average of 21 percent thicker in individuals with migraine, the team found.
It's not clear why this thickness varies in people with and without migraines.
"The brain is a plastic organ, and its structure can change depending on whether you're using it or not," Hadjikhani said. "Now, the question is, do we see the increase in thickness because we have repetitive attacks of migraine? That's our interpretation. The idea is, if you are stimulating this system three or four times a month since you were a teenager, maybe it makes it bigger."
And changes in the brain induced by repetitive migraine attacks may make sufferers more prone to suffering from other pain disorders, the researchers theorized. This would explain the high number of people with migraine who also suffer from such conditions as fibromyalgia and back pain.
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