title: Functional connectivity changes between parietal and prefrontal cortices in primary insomnia patients: evidence from resting-state fMRI.
abstract: BACKGROUND
  Primary insomnia can severely impair daytime function by disrupting attention and working memory and imposes a danger to self and others by increasing the risk of accidents. We speculated that the neurobiological changes impeding working memory in primary insomnia patients would be revealed by resting-state functional MRI (R-fMRI), which estimates the strength of cortical pathways by measuring local and regional correlations in blood oxygen level dependent (BOLD) signs independent of specific task demands.
  
  
  METHODS
  We compared the R-fMRI activity patterns of 15 healthy controls to 15 primary insomnia patients (all 30 participants were right-handed) using a 3.0 T MRI scanner. The SPM8 and REST1.7 software packages were used for preprocessing and analysis. Activity was expressed relative to the superior parietal lobe (SPL, the seed region) to reveal differences in functional connectivity to other cortical regions implicated in spatial working memory.
  
  
  RESULTS
  In healthy controls, bilateral SPL activity was associated with activity in the posterior cingulate gyrus, precuneus, ventromedial prefrontal cortex, and superior frontal gyrus, indicating functional connectivity between these regions. Strong functional connectivity between the SPL and bilateral pre-motor cortex, bilateral supplementary motor cortex, and left dorsolateral prefrontal cortex was observed in both the control group and the primary insomnia group. However, the strength of several other functional connectivity pathways to the SPL exhibited significant group differences. Compared to healthy controls, connectivity in the primary insomnia group was stronger between the bilateral SPL and the right ventral anterior cingulate cortex, left ventral posterior cingulate cortex, right splenium of the corpus callosum, right pars triangularis (right inferior frontal gyrus/Broca's area), and right insular lobe, while connectivity was weaker between the SPL and right superior frontal gyrus (dorsolateral prefrontal cortex).
  
  
  CONCLUSIONS
  Primary insomnia appears to alter the functional connectivity between the parietal and frontal lobes, cortical structures critical for spatial and verbal working memory.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Li
authors.forename: Enfeng
authors.initials: E
authors.lastname: Wang
authors.forename: Hongju
authors.initials: H
authors.lastname: Zhang
authors.forename: Shewei
authors.initials: S
authors.lastname: Dou
authors.forename: Liya
authors.initials: L
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Tong
authors.forename: Yu
authors.initials: Y
authors.lastname: Lei
authors.forename: Meiyun
authors.initials: M
authors.lastname: Wang
authors.forename: Junling
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Radiology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China. shidapeng0904@126.com.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Shi
authors.forename: Qingyong
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D012146:Rest; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology*; D055815:Young Adult