Migraine chronification is associated with beta-band connectivity within the pain-related cortical regions: a magnetoencephalographic study.

Pain disorders are associated with aberrant oscillations in the pain-related cortical regions; however, few studies have investigated the relationship between the functional cortical network and migraine chronification through direct neural signals. Magnetoencephalography was used to record the resting-state brain activity of healthy controls as well as patients with episodic migraine (EM) and chronic migraine (CM). The source-based oscillatory dynamics of the pain-related cortical regions, which comprises 10 node regions (the bilateral primary [SI] and secondary somatosensory cortices, insula, medial frontal cortex, and anterior cingulate cortex [ACC]), were calculated to determine the intrinsic connectivity and node strength at 1 to 40 Hz. The total node strength within the pain-related cortical regions was smaller in the beta band in patients with migraine (70 EM and 80 CM) than in controls (n = 65). In the beta band, the node strength and functional connectivity values of patients with CM and patients with EM differed from those of controls in specific cortical areas, notably the left SI (EM < control) and bilateral ACC (CM < control); moreover, the node strength was lower in patients with CM than in those with EM. In all patients with migraine, negative correlations were observed between headache frequency and node strength in the bilateral ACC. In conclusion, migraine is characterized by reduced beta oscillatory connectivity within the pain-related cortical regions. Reduced beta connectivity in the ACC is linked to migraine chronification. Longitudinal studies should verify whether this oscillation change is a brain signature and a potential neuromodulation target for migraine.