Now we cannot dismiss the complaint of migraine sufferers by simply
saying that they whine about light hurting during their headache. A research
finding has stated reasons about why light exacerbates the already
debilitating pain of migraines, even in some blind people. A recent online
report published in Nature Neuroscience reveals how visual and pain pathways
in the brain converge to produce this phenomenon.
Why light hurts during migraines?
The research findings are
unlikely to help migraine patients in the near future by improving the
anti migraine
drugs. However, according to Dr. Michael Palm, "this gives us a
little better insight as to the theory and mechanism behind migraine."
Dr. Palm is an assistant professor of neuroscience and experimental
therapeutics and internal medicine at Texas A&M Health Science Center
College of Medicine, College Station, and director of the Parkinson's and
Headache programs at Texas Brain and Spine Institute in Bryan. The reason
cited for migraine sensitivity to light says that there are cells in a part
of the brain called the thalamus where information from the visual system
and information from the pain system converge. This anatomic convergence
leads to light making head pain worse. Thalamus is the brain's sensory
switchboard that receives sensory signals from different parts of the body
and then redirects them to various sensory, motor and cognitive areas of the
cortex.
How the conclusion was made?
Based on one of the major migraine
symptoms- photophobia- the researchers designed their strategy for studying
migraine sensitivity to light. About 85 to 90% of all migraine sufferers
report having photophobia, which is when light makes the pain worse. The
research team studied 20 blind individuals who suffered from migraines. Six
of these participants had no light perception at all and no functioning
optic nerve. These individuals did not experience any photophobia. The rest
of the 14 people could sense light and dark and also experienced
photophobia. This made the researchers understand that the optic nerve is
critically needed to produce photophobia or exacerbation of the headache by
light.
The next discovery of these researchers was that a set of photoreceptors
called melanopsin project onto neurons on the thalamus that also process
pain signals. At this stage they needed to follow in the brain the pathways
that lead from the eye into the brain using the third group of
photoreceptors. As such, they shifted to animals for their further study. In
their attempt to find why light hurts during migraine, the reasearchers
identified a new pathway in the brain that originates in the eye and goes to
the brain areas where neurons are found that are active during migraine
attacks. Now they knew that light can increase the electrical activity in
neurons that are active to begin with. This provides an anatomic and
physiological basis for a common experience felt by all migraine sufferers.
Light hurts during migraine because there is an anatomic pathway that links
the visual system to the pathway that produces head pain.
Read
Migraine
Headache Home Remedies
Injection