Increased insular connectivity with emotional regions in primary insomnia patients: a resting-state fMRI study

To explore the abnormal connectivity patterns between the insular and the voxels of the brain in primary insomnia (PI) with insular-based functional connectivity (FC).

With the resting-state fMRI data acquired from 57 PI patients and 46 healthy controls, a two-sample t test was performed on individual FC correlation maps from two groups. The person correlation analysis was used to evaluate the relationship between the abnormal FC and clinical features.

PI patients show enhanced connectivity between the left insula with the right anterior cingulate cortex (p < 0.05 and p < 0.001, AlphaSim-corrected), right frontal sup orb, bilateral thalamus and left precuneus,as well as decreased connectivity with the left middle temporal gyrus and right fusiform (p < 0.05, AlphaSim-corrected). Correlation analysis indicated the enhanced connectivities in the PI patients have significant negative correlations with Self-Rating Depression Scale(SDS)and Self-Rating Anxiety Scale(SAS)scores. In addition, the decreased functional connectivities showed positive correlations with SDS and SAS scores.

Our study showed the increased connectivity regions with insula were mainly in the emotional circle and decreased connectivity was in cognitive-related regions. These provide additional evidence from functional integration view to understand the possible underlying neural- mechanisms of PI.

• The aberrant insular-based connectivity pattern of PI patients was detected. • Regions showing increased connectivity with left insular were mainly in emotional circle. • Significant correlations between changed FC and SDS and SAS score were found.