Objective: To investigate the changes in the functional connectivity in the right insula between migraine without aura and healthy controls by using resting-state functional magnetic resonance imaging (rs-fMRI), and to observe the instant alteration of functional connectivity in migraine without aura during electroacupuncture stimulation at Shuaigu (GB 8).
Methods: A total of 30 patients with migraine without aura (PM group) and 30 healthy controls (HC group) underwent rs-fMRI scans. The PM group underwent a second rs-fMRI scan while receiving electroacupuncture at GB 8. The right insula subregions, including the ventral anterior insula (vAI), dorsal anterior insula (dAI) and posterior insula (PI), were selected as the seed points for functional connectivity analysis.
Results: Aberrant functional connectivity, including dAI with right postcentral gyrus, PI with left precuneus, was found among PM before electroacupuncture (PMa), PM during electroacupuncture (PMb) and HC. Meanwhile, decreased functional connectivity between dAI and the right postcentral gyrus was found in the PMa compared to the HC and PMb. Increased functional connectivity between the PI and left precuneus was found in the PMa compared to the HC and PMb.
Correlation analysis showed that the functional connectivity value of the right postcentral gyrus in PMa was negatively correlated with the scores of Hamilton Rating Scale for Depression and Hamilton Rating Scale for Anxiety. The functional connectivity value of the left precuneus in PMa was positively correlated with the visual analogue scale score.
Conclusion: The alteration of functional connectivity between the right insula subregions and multiple brain regions may be an important index for migraine without aura. electroacupuncture at Shuaigu (GB 8) was able to adjust the functional connectivity between the right insula subregions and parietal lobe, namely, the right dAI and right postcentral gyrus, and the right PI and left precuneus, thereby rendering an instant effect in the management of migraine without aura.