visual cortex Archives - Headache and Migraine News

visual cortex

28 February 2020

Is Your Vision Overly “Sensitive” – even when you don’t have a headache?

If you feel like you are still overly sensitive to visual stimulation even when you’re not in the middle of a migraine attack – you’re not alone. And a new study has confirmed this once again.

There is still probably a common misconception that people with migraine simply have headaches once in a while – bad ones, yes. But that means a bad day, and then it’s all over.

But people with migraine know better. Not only is a migraine attack much more than just a headache, it also often starts before the headache starts, and ends long after. In fact, there are many ways in which migraine affects all of life.

Researchers are continually discovering ways in which the biology of migraine patients is simply different – even in between attacks. (See for example After a Migraine: Vision Problems and Stroke Risk?) A study published this year in NeuroImage: Clinical focuses on sensitivity to visual stimuli.

This particular trial used both objective tests such as EEGs as well as subjective questions to measure “visual symptoms” between migraine patients and controls. One key element used was “gratings” – symmetrical lines – which tend to be unpleasant to look at (and so apologies for the image above, but it illustrates the point).

We know that migraine patients are very much focused on visual discomfort during and even between attacks. Special glasses, avoiding light, using “dark mode”, and even issues with driving past a series of symmetrical posts with the sun shining through them – these are all well known in the migraine community.

This trial confirmed that migraine patients are unusually “sensitive” to visual stimuli. We feel more discomfort than the average person.

This discomfort is similar to what non-migraine patients feel if they are also extra sensitive, though they seem to be generally less-sensitive.

So there is an underlying pattern here, which researchers believe is centred on the visual cortex (located at the back middle section of your brain). The study’s lead author summarized this way:

Most migraineurs also report experiencing abnormal visual sensations in their everyday life, for example, elementary hallucinations, visual discomforts and extra light sensitivity. We believe this hints at a link between migraine experiences and abnormalities in the visual cortex. Our results provide the first evidence for this theory, by discovering a specific brain response pattern among migraineurs.
Dr. Terence Chun Yuen Fong

The next step will be to measure changes before, during, and after a migraine attack. A better understanding of visual sensitivity not only helps us understand migraine better, it may help us to be able to better predict and treat specific attacks.

Meanwhile, don’t brush off that “discomfort” you may be feeling between attacks. It might just be a part of the bigger picture of migraine itself.

Full study available here: Differences in early and late pattern-onset visual-evoked potentials between self- reported migraineurs and controls via The brain of migraine sufferers is hyper-excitable

15 November 2013

Are Migraine Researchers Preoccupied with Pain?

James Discoveries & Stats 13

There’s no doubt that, for most people with migraine, pain is a big concern. But the truth is, pain is not the only symptom of migraine. And it could be that our focus on pain is hindering research.

Dr. Peter Goadsby of the University of California San Francisco Medical Center, is one of the researchers who is concerned that too many are focused on pain, thinking that the pain of migraine is simply causing other symptoms.

Of course, many migraine sufferers will realize that this idea is suspect. After all, what about the symptoms that typically appear before the pain?

But another question is, what about the symptoms that often go with the pain? Is pain simply causing nausea, or is the nausea simply caused by an underlying problem? What about the feeling of heaviness some patients describe, or sensitivity to light?

There is a lingering supposition that pain is simply causing problems in the head – changes in blood vessels, for example. But if there’s an underlying condition of the brain that leads to most migraine symptoms – we must find a treatment for that condition.

Dr. Goadsby’s Study: A Disorder of the Brain

In a study presented earlier this year, Dr. Goadsby believes he has confirmed yet again that migraine symptoms come from a disorder of the brain. In his words:

This is an important step in solidifying our ideas that migraine is fundamentally a disorder of the brain, not a disorder of structures outside the brain. We were able to address the question that people have wondered about for many, many years, that is, what is the degree to which pain is driving the initial symptomatology â€” and we got clear answers to that.

The study used brain scans, but did something that is rare in migraine research. Brains were scanned before the headache hit. This allowed researchers to study migraine symptoms that were present before there was any pain.

So were there changes in the brain before headache? You guessed it – the answer is yes. And we have been able to get a glimpse into which parts of the brain change in the “early stages” of an attack.

For example, the hypothalamus. Just above the brainstem, the hypothalamus is known to be key in cluster headache. It’s key for functions like sleep and mood.

The midbrain was also involved, confirming earlier studies.

The visual cortex was active in patients with visual problems. And the medulla in the brainstem was active in patients experiencing nausea.

This may all seem rather obvious, but the key here is that these patients had not yet experienced migraine headache. So in the case of nausea, for example, it could be that it’s not dependent on the pain, but simply another result of the changes in the brain that cause migraine. Dr. Goadsby explains:

…it’s entirely plausible that those areas are activated by the migraine process and that’s why nausea and vomiting are so common in migraine; it’s not simply a response to the pain … It was thought that nausea and pain were highly linked, but that doesn’t seem to necessarily be the case.

A New Research Manifesto?

Treating symptoms is very important – but we want a cure to migraine – a cure that will end all migraine symptoms.

Research and treatment need to be dealing with the brain. The other symptoms of migraine need to be taken seriously, so that we’re not just stopping pain (often that approach doesn’t work anyway), but stopping migraine.

Patients also need to be cautious of “treating pain” with “painkillers”, and instead look to a complete and targeted migraine treatment plan.

Dr. Goadsby hopes that there will be a shift in thinking when it comes to migraine. “From a big picture treatment perspective, this says to me that we probably won’t get away with developing drugs that don’t get into the brain to have substantial effects on migraine prevention”.