Functional connectivity alterations of orbitofrontal cortex in chronic insomnia

Many neuroimaging studies have been done, to illustrate neuropathology of chronic insomnia, as one of the most common psychological disorders. Recent studies, emphasis on the role of orbitofrontal cortex. But the functional connectivity of OFC hasn’t been studied yet. To the best of our knowledge, it is the first study to discuss about it.

In a case-control study, functional connectivity of OFC with whole brain was carried out to compare the functional connectivity alterations of this region between forty-two chronic insomnia patients, obtained at sleep disorders research center in Kermanshah university of medical sciences, and fifty-two healthy controls without sleep problems. Additionally, Pittsburgh Sleep Quality Index and nocturnal polysomnography was taken from subjects.

Patients showed decreased inter-functional connectivity of right OFC and intra functional connectivity of right OFC with right frontal pole, right insular cortex, right and left inferior frontal gyrus, left middle temporal gyrus and right frontal operculum cortex. Additionally, the functional connectivity of right OFC with precentral gyrus was increased in patients compared with controls (p<0.05 corrected for multiple comparisons). Above mentioned alterations were significantly correlated with subjective sleep quality.

Our results show functional connectivity alterations of OFC in patients in comparison to healthy controls and these changes are correlated with subjective sleep quality. Therefore, this cortex can discuss some signs of chronic insomnia and even same neuropathology with depression.