Patients with chronic migraine (CM) have a stronger connectivity in the pain matrix compared with patients with episodic episodes, a recent study found. Researchers prospectively recruited patients aged 18-60 years with earlier episodic migraine (EM) or chronic migraine. All patients underwent 3T MRI using an identical scanner. Patients were considered interictal if they did not have a migraine headache at the day and ±1 days of functional MRI acquisition. Connectivity analysis with a weighted and undirected network model was performed. The between-group differences in degree centrality (DC) values were assessed using 5,000 permutation tests corrected with false discovery rate (FDR). Among the findings:

• 62 patients (44 EM and 18 CM) were enrolled in the study.
• Among the 7 functionally interpretable spatially independent components (ICs), only the pain matrix showed a significant between-group difference in DC.
• The pain matrix was functionally correlated with the hypothalamus and dorsal raphe nucleus with different levels of strength in EM and CM.