As I searched for the reasons why people, or myself in particular, had attacks of migraines on a non scientific basis, just by observation, I was convinced it had something to do with the build-up of wrong chemicals in the brain, thus effecting the firing of the neurons or brain cells, plus the blood supply to the brain.
I had observed that on the now rare occasions I had an attack of migraine, I was not drinking, therefore I was dehydrated, and not washing away the unwanted chemicals, the body waste.
As I had a migraine, I also observed that the blood vessels at the side of the head, the temples, were more pronounced, they stood out. At the moment as I run my finger tips over the temples I can feel no blood vessels. Therefore migraine could be a vascular disorder.
This months (July 2008) Scientific American, published an article by David W. Dodick and J. Jay Gargus entitled “Why Migraines Strike“.
In this article they describe the various symptoms reported by sufferers, and the old views, as was mine that migraines were cause by blood pressure. But with new technology and research, brain imaging, molecular biology and genetics, new understanding has emerged, and from these new understandings possible new treatments.
They now know that prior to a migraine attack, there could be an increase of up to 300% in blood supply, and then a drop to near normal or below. So yes blood circulation is a factor, but read on.
Prior to the pain part of the disorder, sufferers often describe visual disturbances, flashing lights, distortion, blank fields of vision, hallucinations or “aura’s“. This is obviously the functionality of the brain, misfiring of the neurons, messages not being transmitted across the brain or incorrect messages.
What they have observed as aura’s. occur, is that in the outer layer of the brain, the cortex, there is an increase of activity, a “brainstorm“, which is also called a cortical spreading depression. This will involve an increase in the blood circulation, as the neurons are highly active. As this depression or hyperexcitability passes, there is a drop in blood demand. This spreading depression across the cortex is quite slow, quoted as 2 – 3 millimeters a minute, thus the aura. effect lasting for say an hour.
When neurons fires, activates, pass-on or transmit information to another neuron, they do so by an electrical charge. This is produced by the neuron releasing neurotransmitters, resulting in the flow of sodium and calcium flowing into membranes and potassium irons to flow out in the opposite direction, thus creating an electrical charge.
The aura effect could be due to disturbances in this transmission system and could be from inherited genes.
It is known that the brain itself has no pain receptors, but one part does. It is known as the trigeminal nervous system. The trigeminal nucleus is located in the brain stem and passes signals through the thalamus, up into the sensory cortex, the part of the brain we have conscious awareness.
The cortical speading depression or “brainstorm” described above, sends signals down to the trigeminal nucleus, through the thalamus into the sensory cortex, thus the pain suffered by migraine sufferers.
The chemicals involved in this transmission are believed to include ions, glutamate and nitric oxide.
Other investigations reveal activity in the brain stem region, the locus coeeuleus, raphe nucleus and the periaqueductal gray, could cause the transmission of pain to the sensory cortex. Also the regions of the limbic and paralimbic cortices can transmit signals resulting in the pain. The later region of the brain regulating mood, arousal and attention, the former, being stimulated by light, smell and sounds.
This new understanding of the workings of the brain durring a migraine attack, is helping the development of new drugs and treatments, which will inhibit the cortical speading depression, the firing if the trigeminal nervous system, and the action of neurotransmitters, and that migraine does exist.
I hope that I have been able to impart some understanding of migraine to you, and that I was not far from the mark in my own observations, that it is a biological process, that is beginning to be understood.
See previous articles.
The start of my migraines.
My migraines get worse as I search for a cure.
Further knowledge on Migraines