Aberrant default mode network in patients with primary dysmenorrhea: a fMRI study

Primary dysmenorrhea (PDM), characterized by cramping pain in the lower abdomen, is a common gynecological disorder in women of child-bearing age. An increasing number of neuroimaging studies have emphasized that PDM is associated with functional and structural abnormalities in the regions related to the default mode network (DMN). Based on resting-state functional magnetic resonance imaging (fMRI), the aim of this study was to use amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) to investigate changes of the intrinsic brain activity in the DMN in PDM. Pearson correlation analysis was conducted to assess relationships between the neuroimaging findings and clinical symptoms. Forty-eight PDM patients and thirty-eight matched healthy controls participated in this study. Compared to healthy controls, PDM patients had increased ALFF in the precuneus, dorsomedial prefrontal cortex (dmPFC) and anterior cingulate cortex (ACC) and decreased ALFF in the thalamus. PDM patients also had decreased connectivity between the precuneus and left dmPFC and right ACC, while increased connectivity between the precuneus and left thalamus. In addition, the ALFF in the left dmPFC in PDM patients positively correlated with disease duration. Our findings provide further evidence of the DMN-related abnormalities in PDM patients which might contribute to a better understanding of the pathophysiology of this disease.