The brainstem has been discussed as the main player in the pathogenesis of migraine. Dysfunctional brainstem nuclei and their abnormal connections to other key brain centers may contribute to headache and other symptoms of migraine. In the present study, 32 patients with migraine without aura (MWoA) and 32 age- and sex-matched healthy controls (HCs) underwent resting-state fMRI scans. We used masked independent analysis (mICA) to investigate whether patients with MWoA exhibited abnormal brainstem nuclei-cortical functional connectivity (FC). The mICA can suppress adjacent physiological noise and prevent results from being driven by the much stronger signals of the surrounding structures. Regional homogeneity (ReHo) was used to investigate whether the brainstem regions with abnormal FC to other brain areas exhibited abnormal regional neuronal activity. Patients with MWoA showed significantly weaker FC between the posterior pons and the left superior parietal lobule, the left middle temporal gyrus, and the left middle frontal gyrus. Furthermore, patients with MWoA exhibited significantly decreased ReHo values in the posterior pons compared with HCs, and the posterior pons ReHo value was significantly negatively correlated with HIT-6 scores in the MWoA group. Patients with MWoA exhibited functional abnormalities in the posterior pons and weakened connections between the posterior pons and several key cortical brain areas involved in pain processing during the resting state.

This study provided increased evidence that the pons is involved in the pathophysiological mechanism of migraine, and weakened connections suggest that the touch and pain sensation of migraine sufferers may not be properly relayed to cortical processing areas, which may be associated with the pathogenesis of MWoA.