A team of scientists from the Beth Israel Diaconesa Medical Center in Boston, USA, have discovered an unknown connection between light-sensitive cells in the eyes and certain nerve cells in the brain involved in the perception of pain, which could explain why light stimuli aggravate pain in migraine patients.
About 20% of people with migraine manifest depression, irritability, restlessness, lack of appetite and sensitivity to light.
The work published in the journal 'Nature Neuroscience', and directed by Rami Burstein, shows that many blind people who suffer from migraines also elude light. In contrast, patients with blindness who had totally lost the eye or the optic nerve connecting the eye with the brain did not avoid light.
Based on these observations, the scientists worked with rats in which they directly searched the connections of the retina with the areas that register pain in the brain, and found that the retinal axons (prolongation of the retinal neurons) sent connections to a group of nerve cells located in an area of the brain - the thalamus - which is responsible for receiving and transmitting pain signals related to migraine. According to the authors, this connection could be the cause why light worsens the pain of migraines.