Altered functional connectivity in a sensorimotor-insular network during spontaneous migraine attacks: a resting-state FMRI study

Background: Previous functional magnetic resonance imaging studies have identified brain-connectivity alterations across multiple regions in people with migraine when compared to healthy controls. Few studies have focused on such changes throughout the different phases of the migraine cycle. We aimed to investigate functional connectivity during spontaneous occurring episodic migraine attacks, in comparison to interictal periods. Methods: Eleven women with episodic migraine without aura underwent two sessions of resting-state fMRI, during and outside of a spontaneous migraine attack. Functional connectivity changes were assessed across canonical resting-state networks, identified by independent component analysis. Significantly altered connectivity was correlated with migraine attack symptoms. Results: Decreased functional connectivity between subregions of the sensorimotor network (specifically, the primary somatosensory and motor cortices) and the posterior insula, bilaterally, was found during attacks. In both sessions, the functional connectivity between these regions was lower in patients who usually suffered longer attacks. Discussion: The sensorimotor and insular regions are involved in nociceptive, autonomic, and somatosensory processing so the finding of reduced connectivity between these structures within a migraine attack is likely associated to the perception of pain and the heighten sensitivity to stimuli experienced in this disorder.