Preliminary fMRI data from Italian and British researchers suggests that complex periodic interactions between networks in different brain regions, including the brainstem, thalamus and hypothalamus, may be responsible for triggering migraines. Imaging studies suggest that a single region of the brainstem may be responsible for triggering migraines. However, this migraine trigger theory has been challenged by other data suggesting that networks involving the hypothalamus may be active in the days leading up to migraine attacks . For this study, fMRI was performed on episodic migraine subjects using a nitroglycerin-induced headache model, and the results were compared to a control group.
Altered networks even before the migraine attack
During the prodromal phase , the functional connectivity of
brainstem nuclei involved in pain circuitry with each other and with the
hypothalamus is impaired (periaqueductal gray
and trigeminal nucleus on the left; right PAG and trigeminal nucleus; dorsal raphe). The connections between the thalamus and the hypothalamus also changed during the prodromal period. Similarly, the left thalamus showed significantly different functional connectivity in the primary phase, involving interactions with the sensory and cerebellar cortex of the frontal lobe. Presenting the results, Dr Daniele Martinelli of the University of Pavia, Italy, concluded that they strengthen the evidence that migraines are triggered by complex cyclical interactions between networks of brain regions, rather than the competing idea of a single migraine triggering nucleus in the brainstem. Martinelli D, et al. Brain networks in migraine: a pilot study using advanced fMRI techniques in experimentally-induced attacks. EAN Virtual Congress 2020;O1019.
