e need pain. It seems contradictory to say it, particularly now that we have so many ways of dealing with it and switching it off. Pain not only tells us something is wrong, it also protects us. If you slam the car door on your hand, it’s going to hurt. You will have damaged the soft tissue; all the muscles and ligaments that help you move your fingers. It will no doubt swell up to twice its size. This inflammation is part of the healing process. Your hand feels hot and looks red because of all the extra blood flow. All these inflammatory agents that are acting to heal you are stimulating the pain receptors in your hand, the ones in your skin and your muscles. Your head is not so different except, crucially, the underlying cause can be much more subtle and varied. As a neuroscientist who writes about headaches, it is somewhat ironic to admit that I suffer from them still. Two recent headaches stand out. The first happened when I couldn’t find my glasses. I’m astigmatic so I see the world on a bit of a slant because my left eyeball is shaped like a rugby ball instead of a football. Just looking around can be effortful. Plus, the search made me late for everything that day which was unpleasant. By the time I got home, my head felt like it was in the grip of giant hands and they had begun to squeeze hard. All I wanted for dinner was a paracetamol sandwich. I can point to many reasons for my headache. Stress is the obvious one, eye strain another. Almost everyone has experienced this kind of tension headache. By the end of the day, my body was so tense I had to unclench my jaw to poke my toothbrush in to brush my teeth. The emotional stress we feel triggers the fight-or-flight response. The adrenaline release widens blood vessels to our vital organs to bring energy and oxygen to help us cope. Couple this with not having slept well the previous night, together with missing lunch and not hydrating well, and the large glass of wine I had the night before, I had created the perfect storm in my head. The discomfort I was feeling was coming from the dilation of the blood vessels in my head. Blood is actually toxic to the brain, which is why it is separated via the “blood brain barrier”. Therefore, if the blood vessels widen for any reason, alarm bells ring. Your brain is the most vital organ you have, so pain is an early warning system for danger. Usually, we pop an anti-inflammatory pill like paracetamol to reduce the blood-vessel dilation, but that isn’t a long-term solution. If we don’t try to relax and switch off, it will keep happening with the release of more long-term chemicals like cortisol that keep your body on high alert. The choices we make to wind down sometimes don’t help either. Those couple of glasses of wine and the takeaway you had to de-stress play with your brain chemistry. Your kidneys need to tap your brain (73% water) to dilute the alcohol and the salts and spices in your meal so they can be safely excreted. This dehydration will make your brain shrink, pulling on the membranes that cover it (the meninges), setting off pain receptors there, too. The second memorable headache I have had was tougher to work out. I can often avoid a migraine before it hits but this particular episode escalated over time. I experienced a throbbing in the right side of my skull every couple of days over the course of two weeks with associated malaise that goes with migraine. I got my eyes tested and watched what I ate, made sure I was hydrated. I just couldn’t work it out. Until I realised the cause lay in my environment. My trigger is well known in the medical literature, and it’s visual. It’s worth noting that the visual areas of the migraineur’s brain are particularly sensitive to lines of all orientations depending on how close they are to each other. Unfortunately, my wife had recently taken to wearing stripy tops of various colours. This can set off the hallmark of the migraine attack – a wave of excitation across the brain quickly followed by a wave of inactivity. Some of us notice this as an “aura”: a sensory disturbance that might be visual or feel like pins and needles. This is called Classic Migraine. But the same thing is happening in the brains of those who don’t get auras, which is simply called Common Migraine. (Ocular Migraine is when you experience the aura without the pain phase). All the neurochemical changes associated with these waves cause a vasoconstriction in the head. Because a lack of blood flow to the brain can be catastrophic, our body reacts with a massive vasodilation in response. Cue the pain-receptor activation and inflammation as we see also in tension headache. The heightened activity in your brain means you will have trouble moving, thinking, remembering things, and of course the gold standard, photophobia. In effect, migraine shuts us down until the proper neurochemical balance is restored. Now that I had identified the problem, I could address it, promptly forbidding my wife to wear her new tops in my presence. We are surrounded by stripes and lines of course, but I am not obliged to look at those so much. There are other triggers for migraine: hormones, diet or even cardiovascular origins. But the real key is understanding what causes your headache, whether it be a sinus, tension, cluster or migraine headache. Of course not every really painful headache is a migraine, in much the same way that a really bad cold is not flu. Migraine has a specific symptom set that means it is recognised now as something totally separate from other classes of headache. The most interesting aspect of migraine is that it goes beyond the headache component. I have spoken to many sufferers in my time and the most fundamental thing I have discovered is that migraineurs are quite bad at spotting the first stage: the “prodrome” phase. Dr Ana Gago-Veiga from the headache unit in Sanitaria Hospital, Madrid, worked out that only a third of patients she surveyed could be classified as good predictors, in that they could spot an impending migraine more than 50% of the time. Even then, it was only because their prodrome symptoms were quite obvious, including pronounced yawning, drowsiness, food craving, adversity to light, increased thirst or blurred vision. These are related to changes happening in your brain and can occur a couple of days or hours before the migraine starts. It takes a certain amount of self-awareness to spot the first stage of a migraine. For many years, professor Peter Goadsby from King’s College London has been talking about the value of tracking these symptoms to their underlying biology. It’s the changes that happen in your brain that sometimes cause the “triggers” for migraine. I am interested in why we have these symptoms. Are they in some way generated to redress some neurochemical balance that is out of kilter in our brain? The best way to prevent them developing is to recognise them by keeping a record of your day: what you ate, how much exercise you took and when, what you drank, how you felt at different points. People tend to only do this when they feel awful, but it is so important to have the contrast with when you felt well. Headaches cost the NHS £250m per year, and the associated cost to the economy is at least £3.42bn every year. Pain is different for everybody, so your GP finds it difficult to get to the root of it in the 10 minutes or so they have with you. Wouldn’t we all prefer more control over our headaches? For example, knowing migraine is linked to depletions in serotonin helps with medical treatment once you have one: the drug sumatriptan acts just like serotonin in the brain. But chocolate contains tryptophan which breaks down into serotonin in your body, so that the chocolate you crave just before a headache is not causing your headache, it is your body trying to self-medicate and restore serotonin balance. Dopamine and oxytocin also block pain receptors, so doing something you love will help boost those. All three are released during orgasm, so sex and intimacy may be medicinal, too. Headaches don’t just live in our head. They give us a fascinating view of how our brain works with our body to create behaviours and alter our feelings. You must listen to your pain, and look at your whole self to see how best to treat it. Splitting: The Inside Story on Headaches, by Amanda Ellison, is published by Bloomsbury at £16.99