What happens in the brain when you get a migraine?

It is a condition brings on crippling pain to nearly five million Aussies and costs the nation billions a year via both the health system and lost productivity costs.

Migraine is one of the world's most common brain conditions.

A migraine is a neurological disorder that causes a severe headache, which normally only affects one side of the head.

READ MORE: Why is Australia so successful at the Olympics?

READ MORE: Just how unaffordable is housing? For one group, it's impossible

Other symptoms can include vomiting, sensitivity to light, sound and smells.

Speech can also be affected and limbs can go numb.

In up to 30 per cent of people who get them, migraine attacks begin with disturbed vision, called an aura.

Doctors don't know why migraines happen.

They affect more women than men.

It's the most common neurological disorder, according to the World Health Organisation.

READ MORE: How stage 3 tax cuts work

What happens to your brain during a migraine?

Migraine is caused by the activation of a network in the brain which controls sensation, as well as central parts of the brain including the brain stem Migraine and Headache Australia explains.

It involves the activation of what are called trigeminovascular pathways.

The trigeminovascular system controls sensation in the face and jaw.

The brain is thought to be in an altered state of excitability, which can lead to symptoms like nausea, light sensitivity and aura.

Meanwhile, when the brain is more sensitive, neurotransmitters - chemical messengers - can become overactive and trigger pain signals.

These neurotransmitters also control things like hunger, wakefulness, anxiety and focus, which can all be affected during or after an attack.

Calcitonin Gene-Related Peptide (CGRP) is an important chemical involved in transmitting pain signals through the nervous system – and it's also associated with the triggering of migraine attacks according to the National Migraine Centre in the UK.

The difficulty in migraine treatment arises because there are often many different neurotransmitters active during an attack, Migraine and Headache Australia says.

The actual pain is often caused by the swelling or inflammation of blood vessels in the brain.

What is the biggest trigger for migraines?

Triggers can include many things.

Other people who get migraines might not be able to find an explanation for what brings one on.

Some can last for hours, while some people can suffer for days.

The most commonly reported food triggers are chocolate, cheese, coffee and other caffeinated drinks, nuts, citrus fruits, processed meats, additives such as monosodium glutamate (MSG) and aspartame (an artificial sweetener), Migraine and Headache Australia says.

Fatty or salty foods and alcoholic drinks, usually red wine and beer can also bring one on, people say.

READ MORE: Peter Hitchener on his struggle with migraines after falling ill on-air

READ MORE: New vaping laws come into effect

Other triggers include bright or flickering lights or motions, strong smells, changes in weather which alter the atmospheric pressure, tiredness, stress, hormones and even skipping meals.

Genetics can also affect whether somebody gets migraines or not.

Having a traumatic brain injury can also cause them.

Experts advise keeping a migraine diary to try and identify triggers.

New Australian research has also identified some reasons people might get migraine.

Those with smaller brains and smaller brain structures are more likely to have them, a study found.

READ MORE: New drug can relieve migraine attack within hours

How do you make a migraine go away?

Trying to avoid triggers can help, but most people who get migraines will turn to medication.

These can include medicines which aim to prevent attacks, and those taken when one come on.

READ MORE: 'A lot of us can't even get out of bed': Living with crippling migraines

Vyepti is one of the newer ones on offer.

Options include simple painkillers like paracetamol, or triptans, which are prescription only.

New anti-CGRP drugs also increasingly an option for chronic migraine.other options such as Botox injections can be a preventative option.

However, over half of all people who suffer from migraines do not respond to treatment at all.

Always check with your GP before embarking on any medication or treatment or to have symptoms diagnosed.