Thalamus May Play A Key Role In Regulating Migraine Pain
May explain why blind migraine sufferers get attacks that are triggered by light
The anatomy of migraine ““ a close look at the neurobiology of the disease ““ focuses on the thalamus, the area of the brain that is involved in sensory perception and regulation of motor functions, in one a major session of the 53rd Annual Scientific Meeting of the American Headache Society meeting here this week.
The session examines the role of the thalamus in regulating pain transmission in migraine, a new understanding of the anatomy of migraine. It will be at 3:15 pm, Thursday, June 3, and is chaired by Michael A. Moskowitz, MD, of the Neuroscience Center at Massachusetts General Hospital and R. Allan Purdy, MD, who is scientific chair of this year’s meeting
“Elegant basic science and clinical experiments have recently demonstrated that the thalamus acts as a sort of railway station and integration center for the transmission of migraine pain,” Dr. Purdy said. “An impulse comes into the ‘station’ and the thalamus regulates how it will be transmitted to the cortex, and the extent to which it is made worse by environmental stimuli, such as light.” We are beginning to understand that the thalamus may be a target for current and future migraine treatments
In a study of blind people, Rami Burstein, professor of anesthesia and critical care medicine at Harvard Medical School in Boston, looked at two groups of blind patients who suffer migraine headaches – the first group included patients totally blind due to eye diseases such as retinal cancer and glaucoma and the second group patients who were legally blind due to retinal degenerative diseases, such as retinitis pigmentosa. Patients in the first group were unable to see images or to sense light and therefore could not maintain normal sleep-wake cycles. Patients in the second group described intensified pain when they were exposed to light, in particular to blue wavelengths.
“This suggested to us that the mechanism of photophobia must involve the optic nerve, because in totally blind individuals, the optic nerve does not carry light signals to the brain,” Dr. Burstein said.
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