title: Graph-theoretical analysis of resting-state fMRI in pediatric obsessive-compulsive disorder.
abstract: BACKGROUND
  fMRI graph theory reveals resting-state brain networks, but has never been used in pediatric OCD.
  
  
  METHODS
  Whole-brain resting-state fMRI was acquired at 3T from 21 children with OCD and 20 age-matched healthy controls. BOLD connectivity was analyzed yielding global and local graph-theory metrics across 100 child-based functional nodes. We also compared local metrics between groups in frontopolar, supplementary motor, and sensorimotor cortices, regions implicated in recent neuroimaging and/or brain stimulation treatment studies in OCD.
  
  
  RESULTS
  As in adults, the global metric small-worldness was significantly (P<0.05) lower in patients than controls, by 13.5% (%mean difference=100%X(OCD mean - control mean)/control mean). This suggests less efficient information transfer in patients. In addition, modularity was lower in OCD (15.1%, P<0.01), suggesting less granular - or differently organized - functional brain parcellation. Higher clustering coefficients (23.9-32.4%, P<0.05) were observed in patients in frontopolar, supplementary motor, sensorimotor, and cortices with lower betweenness centrality (-63.6%, P<0.01) at one frontopolar site. These findings are consistent with more locally intensive connectivity or less interaction with other brain regions at these sites.
  
  
  CONCLUSIONS
  Relatively large node size; relatively small sample size, comorbidities in some patients.
  
  
  CONCLUSIONS
  Pediatric OCD patients demonstrate aberrant global and local resting-state network connectivity topologies compared to healthy children. Local results accord with recent views of OCD as a disorder with sensorimotor component.
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States.
authors.forename: Casey C
authors.initials: CC
authors.lastname: Armstrong
authors.affiliation: Division of Adult Psychiatry, UCLA Semel Institute for Neurosciences, Los Angeles, CA, United States.
authors.forename: Teena D
authors.initials: TD
authors.lastname: Moody
authors.affiliation: Division of Adult Psychiatry, UCLA Semel Institute for Neurosciences, Los Angeles, CA, United States.
authors.forename: Jamie D
authors.initials: JD
authors.lastname: Feusner
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States.
authors.forename: James T
authors.initials: JT
authors.lastname: McCracken
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States.
authors.forename: Susanna
authors.initials: S
authors.lastname: Chang
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States.
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Levitt
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Piacentini
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neurosciences, 760 Westwood Plaza, Los Angeles, CA 90024-1759, United States. Electronic address: joneill@mednet.ucla.edu.
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Neill
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology*; D009771:Obsessive-Compulsive Disorder / Q000503:physiopathology*; D012146:Rest
keywords: Frontal pole; Obsessive-compulsive disorder; Sensorimotor cortex; Supplementary motor cortex; fMRI graph theory