We may be one step closer to knowing what causes a migraine, which could help determine what parts of the brain to target for future treatments.
and it affects women three times as much as men, although we don鈥檛 know why. Studying migraines has proved difficult because symptoms are sporadic and can last for days, while the MRI machines required to record them are typically in high demand for clinical purposes.
It is also hard to convince people to climb into a noisy and disorientating MRI machine when they are nauseous and have a throbbing headache, but Anne Stankewitz at Ludwig Maximilian University Munich, Germany, and her colleagues were able to do just that.
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鈥淢igraineurs are used to suffering,鈥� said Stankewitz. 鈥淭hey are willing to contribute to research in order to find a better understanding of their disease.鈥�
The team signed up 50 people with migraines and told them to ring when they first started getting a headache. When a call came in, the team would check if an MRI machine was free, and if so bring the person in and scan them. The machine records the brain鈥檚 blood flow levels, a measure of neural activity.
The participant would then come back repeatedly so their brain could be recorded throughout an entire migraine cycle, the period before, during and after a single migraine attack, which can last for days. This scanning took place early in the morning before the machine was needed for clinical use.
Recording was ended when the participant rang to say they had started to undergo a second migraine attack. Of the pool of 50 people on retainer, the researchers got complete data for 12 of them, 11 women and one man. The shortest migraine cycle they recorded lasted seven days, while the longest ran for 21 days.
The team found that joint activity between the hypothalamus and limbic system was key to a migraine attack. Among other things, the limbic system is involved in regulating emotion and pain, while the hypothalamus acts as a sort of metronome for brain activity.
During a migraine attack, the level of connectivity between the hypothalamus and limbic system was low. This level gradually increased after the migraine had passed, reaching its peak just before the next migraine attack began.
鈥淭his may be the hypothalamus trying increasingly harder to keep limbic brain areas under control but ultimately failing,鈥� says Stankewitz. The researchers suggest that migraine attacks are due to this loss of control. 鈥淥ur study underlines the importance of focusing on the phase prior to the headache, where various trigger factors can pave the way for an upcoming attack,鈥� she says.
Stankewitz speculates that people who get migraines may have a genetically faulty link between the hypothalamus and limbic system. She notes that although men and women may have different triggers for their attacks, this mechanism for how migraines start is probably shared.
鈥淭he research itself is a phenomenal logistical operation, but I don鈥檛 know if I would say so strongly that these results show that the hypothalamus loses control of the limbic system during a migraine,鈥� says Amanda Ellison at Durham University, UK. However, the link between these brain regions may have another effect, she says. 鈥淸It] could explain why some migraine sufferers feel a high after recovering from a headache, as the limbic system is involved in emotions.鈥�
Reference: bioRxiv,
