Everything indicates that the pain of migraine occurs when the meninges – the system of membranes that surround the brain and the central nervous system – are irritated and the pain receptors in the area are stimulated. This explains the throbbing pain and tension in the neck that afflicts migraine sufferers. But until now it was not understood why 85% of migraine patients also suffer from photophobia or extreme sensitivity to light , which forces them to wear sunglasses, sometimes even at night.
Scientists at the Beth Israel Deaconess Medical Center in Boston, USA, led by Rami Burstein, have found that many blind people with migraines also avoid light. By analyzing the brains of these subjects, the researchers found that in the presence of light certain neurons in the retina sent signals to a group of nerve cells in the area of the brain known as the thalamus that receives and transmits pain signals associated with migraine headaches. As a consequence, pain neurons increase their activity . And the increase in the intensity of the pain could remain even up to 20 or 30 minutes after the light stimulus disappeared.
The finding, published in the latest issue of the journal Nature Neuroscience , could lead to future treatments for the annoying photophobia associated with headaches.
