Altered gray matter volume in primary insomnia patients: a DARTEL-VBM study

Previous neuroimaging studies have reported brain morphological alterations and the occurrence of mental disorders in primary insomnia (PI) patients. However, studies of the effect of disrupted sleep on brain structure have showed inconsistent results. In this study, DARTEL-VBM was used to evaluate the changes in gray matter volume from 60 PI patients and 53 controls. Voxel-wise statistics was performed in two ways. One is a more liberal statistical analysis using an uncorrected P < 0. 001 with 25 voxels, and the other one is a more conservative approach using a threshold of P < 0.05, corrected for multiple comparisons using the Gaussian random field (GRF) method. Partial correlation was used to analyze the relationship between abnormal volume and clinical features. PI patients had reduced gray matter volume primarily in the right middle cingulate cortex with correction (P < 0.05). Correlation analysis showed gray matter changes in the left middle cingulate cortex were negatively associated with self-ratings for anxiety and depression. This study showed that gray matter deficits in cingulate cortex in patients with insomnia, and the decreased gray matter volume may be associated with the difficulties in emotional management due to insomnia. Functional roles of the affected regions in emotion and regulation of sleep might provide supplementary evidence and guide further research that may facilitate understanding the mechanisms underlying insomnia.