Abnormal functional connectivity in the frontal hub regions of patients with primary insomnia: a resting-state functional magnetic resonance imaging study

Background Primary insomnia (PI) is one of the most common sleep disorders. Diagnosis of insomnia is mainly based on subjective sleep difficulties, and it is still necessary to find objective neurobiological markers. Purpose To investigate the functional connectivity (FC) of frontal hub regions important for PI. Material and Methods We enrolled 20 patients (5 men, 15 women) with PI and 20 controls (5 men, 15 women), matching age, sex. We used resting-state functional magnetic resonance imaging (fMRI) and voxel-mirrored homotopic connectivity (VMHC) to analyze the abnormal changes of FC in the frontal lobe of PI patients. Results Compared to controls, abnormal FC regions were mainly concentrated in the superior frontal gyrus (L/R), middle frontal gyrus (L/R), and inferior frontal gyrus (L) of the orbital region and the inferior frontal gyrus of the opercular region (L) ( P < 0.05). The VMHC results showed abnormal FC in the middle frontal gyrus of the orbital region (GFR correction, voxel P < 0.01, cluster P < 0.025) in PI patients. The FC between the orbitofrontal gyrus and the inferior frontal gyrus of the opercular region with the frontal gyrus of the medial orbital region demonstrated a significant correlation with the clinical scale ( p < 0.05). Conclusion Our study identified abnormal FC, which was mainly located in the orbitofrontal gyrus and the inferior frontal gyrus of the opercular region, in the frontal lobe of patients with insomnia using resting-state fMRI. This is helpful to understand the abnormal neural activity mechanism of insomnia in the frontal lobe and provide a relatively accurate brain region basis for future prevention, diagnosis, and treatment.