Functional Connectivity Abnormalities Of Brain Regions With Structural Deficits In Primary Insomnia Patients

Insomnia is the most common sleep disorder in clinic,which is manifested in difficulty in falling asleep and maintaining sleep,frequent waking up in the middle of the night and early waking up in the morning.The incidence rate of insomnia is high,and the general population of 30-50% has insomnia symptoms,and the incidence rate is on the rise.Primary insomnia refers to insomnia lasting for at least one month,not caused by other mental disorders,physical diseases,material and substance use,or other specific sleep disorders.Primary insomnia has a wide-ranging impact on patients’ quality of life,physical damage,and increased medical costs.More importantly,insomnia has been recognized to be a substantially increased potential trigger for the development of other mental illnesses,such as depression.Previous work has demonstrated that insomnia individuals are approximately 10 times more likely to develop depression as compared with good sleepers,and approximately 90% of patients with depression also suffer from insomnia.Insomnia has been recognized as a serious global problem,and research on the neurobiological mechanism of insomnia is urgent.In the past few decades,there are many studies on the structural and resting state analysis of insomnia,and found that primary insomnia is related to changes in brain structure and abnormal brain function.However,there are limitations to the study of single modalities.Therefore,this paper attempts to explore the abnormal functional connections in the brain regions of gray matter(GM)volume changes in patients with insomnia by combining multiple modalities.The method is a combination of voxel-based morphometry(VBM)and resting state functional connection(RSFC).Thirty-three primary insomnia patients and 38 gender and age-matched healthy controls were selected.The VBM was used to analyze the changes in GM volume between the two groups of subjects,the brain regions showing altered GM volume in PI patients compared with healthy controls were defined as ROIs.Using these ROIs as seed points,the average time series was extracted as the reference time series.And obtain a figure relevant to functional connectivity between average fMRI time series of each ROI and all voxels in the brain.Finally,Pearson analysis was used to study the association between imaging data and clinical variables in patients with PI.We found GM volume in several brain regions decreased in PI patients,i.e.the left DLPFC,left OFC,bilateral MFC,right IFG and left inferior temporal gyrus.The GM volume in the right MFC had a negative correlation with SRSS score and GM volume in the right IFG was negatively correlated with ISI score.Furthermore,PI patients showed decreased RSFC between the right IPC and the right MFC,and between the left OFC and right IFG.The RSFC between the right MFC and right IPC was negatively correlated with SRSS scores.The RSFC between the right IFG and left OFC was negatively correlated with ISI scores.We hope our results may provide novel insights into the neural mechanisms of PI by combining structural and functional modality information.