title: Topological organization of the "small-world" visual attention network in children with attention deficit/hyperactivity disorder (ADHD).
abstract: BACKGROUND
  Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed childhood psychiatric disorder. Disrupted sustained attention is one of the most significant behavioral impairments in this disorder. We mapped systems-level topological properties of the neural network responsible for sustained attention during a visual sustained task, on the premise that strong associations between anomalies in network features and clinical measures of ADHD would emerge.
  
  
  METHODS
  Graph theoretic techniques (GTT) and bivariate network-based statistics (NBS) were applied to fMRI data from 22 children with ADHD combined-type and 22 age-matched neurotypicals, to evaluate the topological and nodal-pairing features in the functional brain networks. Correlation testing for relationships between network properties and clinical measures were then performed.
  
  
  RESULTS
  The visual attention network showed significantly reduced local-efficiency and nodal-efficiency in frontal and occipital regions in ADHD. Measures of degree and between-centrality pointed to hyper-functioning in anterior cingulate cortex and hypo-functioning in orbito-frontal, middle-occipital, superior-temporal, supra-central, and supra-marginal gyri in ADHD. NBS demonstrated significantly reduced pair-wise connectivity in an inner-network, encompassing right parietal and temporal lobes and left occipital lobe, in the ADHD group.
  
  
  CONCLUSIONS
  These data suggest that atypical topological features of the visual attention network contribute to classic ADHD symptomatology, and may underlie the inattentiveness and hyperactivity/impulsivity that are characteristics of this syndrome.
authors.affiliation: Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA.
authors.forename: Shugao
authors.initials: S
authors.lastname: Xia
authors.affiliation: The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Pediatrics, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Foxe
authors.affiliation: Ferkauf Graduate School of Psychology, Yeshiva University Bronx, NY, USA.
authors.forename: Ariane E
authors.initials: AE
authors.lastname: Sroubek
authors.affiliation: Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Radiology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Physiology and Biophysics, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Branch
authors.affiliation: Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Radiology, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA ; Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Yeshiva University Bronx, NY, USA.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Li
keywords: ADHD; Attention; fMRI; functional connectivity; graph theoretic techniques; network-based statistic; small world network