Migraine
Headache Disorder
Side view
Midline view
A neurological condition causing recurrent, often severe headaches, frequently accompanied by nausea and sensitivity to light or sound, and in some cases preceded by visual or sensory 'aura' symptoms.
Common Signs & Symptoms
- Throbbing or pulsing head pain, often on one side
- Nausea, and sometimes vomiting
- Heightened sensitivity to light, sound, or smell
- Visual aura in some cases - flashing lights, zigzag lines, or blind spots preceding the headache
- Premonitory symptoms hours before an attack, such as yawning, food cravings, or mood change
Why These Symptoms Happen
Each symptom can be traced, at least in part, to the job a particular part of the brain normally does. These links are simplified: real symptoms usually come from several connected regions.
| Symptom | Brain region | Why it happens |
|---|---|---|
| Yawning, food cravings, and tiredness before an attack | Hypothalamus | The hypothalamus regulates hunger, sleep, and body rhythms. Brain scans suggest it becomes more active in the day before the headache, which may explain these early warning signs. |
| Zigzag lines or flashing lights (aura) | Occipital Lobe | A slow wave of electrical activity, followed by a period of quiet, spreads across the visual cortex at a few millimetres a minute. As it travels, the disturbance moves across the field of vision. |
| Throbbing head pain | Brain Stem | Pain signals from the coverings of the brain travel along the trigeminal nerve to its nucleus in the brain stem. In migraine, this pathway becomes activated and sensitised. |
| Sensitivity to light and sound | Thalamus | The thalamus relays sensory signals to the cortex. During an attack, pain-sensitised thalamic neurons may amplify ordinary light and sound until they become uncomfortable. |
Overview
Migraine is a neurological condition, not simply "a bad headache" - it involves a distinct sequence of brain changes that can include a premonitory phase, sometimes an aura, the headache itself, and a lingering "postdrome" phase, though not everyone experiences all stages. Roughly a quarter of people with migraine experience aura, most often visual disturbances that develop gradually over minutes, thought to result from a wave of altered electrical activity spreading slowly across the cortex known as cortical spreading depression.
Affected Brain Regions
The head pain of migraine is driven largely by activation of the trigeminovascular system, centred on the trigeminal nerve pathways within the brain stem, which supply sensation to the head and face. The thalamus is thought to amplify and relay these pain signals to the cortex, and altered thalamic activity may contribute to the light and sound sensitivity common during attacks. When aura occurs, the occipital lobe's visual cortex is usually the starting point of the spreading wave responsible for visual symptoms. Increased activity in the hypothalamus in the hours before an attack is believed to underlie many premonitory symptoms.
How It's Studied
There's no scan or blood test for migraine; it's diagnosed from the pattern of attacks. International criteria describe migraine as repeated headaches lasting 4 to 72 hours, with features such as one-sided or throbbing pain, worsening with routine activity, and nausea or sensitivity to light and sound. Brain scans are mainly used to rule out other causes when symptoms are unusual.
Researchers have caught migraine in the act. In 2001, Nouchine Hadjikhani and colleagues used functional MRI while people experienced visual aura and watched a wave of changing activity creep across the visual cortex at about 3.5 mm per minute - matching the speed of cortical spreading depression seen in animals. In 2016, Laura Schulte and Arne May scanned one person with migraine every day for a month and found hypothalamic activity rising in the 24 hours before each headache.
Common Myths
"A migraine is just a bad headache."
Migraine attacks can last up to three days and come with nausea, vomiting, aura, and extreme sensitivity to light and sound. The World Health Organization ranks migraine among the leading causes of disability worldwide.
"Only women get migraine."
Migraine is about three times more common in women, partly because of the influence of hormones, but men and children get it too.
"Migraine always comes with an aura."
Only around a quarter of people with migraine ever experience aura. Most attacks occur without one.
Current Research Directions
A newer class of medications targeting CGRP, a molecule released by activated trigeminal nerves that promotes pain and inflammation, has significantly expanded both acute and preventive treatment options over the past decade. Non-invasive neuromodulation devices, which deliver mild electrical or magnetic stimulation to disrupt migraine-related brain activity, represent another growing treatment avenue. Research continues into the precise mechanism of cortical spreading depression and why some people experience aura and others don't.
Key Terms
Related Brain Regions
Explore the regions involved in migraine in more depth:
This article is for general education and isn't a substitute for professional medical advice or diagnosis. Seek urgent medical help for a sudden, severe 'worst ever' headache, or a headache with weakness, confusion, or a stiff neck and fever.
Sources & Further Reading
- Migraine - National Institute of Neurological Disorders and Stroke
- Migraine - NHS
- Mechanisms of migraine aura revealed by functional MRI in human visual cortex - Hadjikhani et al. (2001), PNAS
- The migraine generator revisited: continuous scanning of the migraine cycle over 30 days and three spontaneous attacks - Schulte & May (2016), Brain