title: Disruption of functional networks in dyslexia: a whole-brain, data-driven analysis of connectivity.
abstract: BACKGROUND
  Functional connectivity analyses of functional magnetic resonance imaging data are a powerful tool for characterizing brain networks and how they are disrupted in neural disorders. However, many such analyses examine only one or a small number of a priori seed regions. Studies that consider the whole brain frequently rely on anatomic atlases to define network nodes, which might result in mixing distinct activation time-courses within a single node. Here, we improve upon previous methods by using a data-driven brain parcellation to compare connectivity profiles of dyslexic (DYS) versus non-impaired (NI) readers in the first whole-brain functional connectivity analysis of dyslexia.
  
  
  METHODS
  Whole-brain connectivity was assessed in children (n = 75; 43 NI, 32 DYS) and adult (n = 104; 64 NI, 40 DYS) readers.
  
  
  RESULTS
  Compared to NI readers, DYS readers showed divergent connectivity within the visual pathway and between visual association areas and prefrontal attention areas; increased right-hemisphere connectivity; reduced connectivity in the visual word-form area (part of the left fusiform gyrus specialized for printed words); and persistent connectivity to anterior language regions around the inferior frontal gyrus.
  
  
  CONCLUSIONS
  Together, findings suggest that NI readers are better able to integrate visual information and modulate their attention to visual stimuli, allowing them to recognize words on the basis of their visual properties, whereas DYS readers recruit altered reading circuits and rely on laborious phonology-based "sounding out" strategies into adulthood. These results deepen our understanding of the neural basis of dyslexia and highlight the importance of synchrony between diverse brain regions for successful reading.
authors.affiliation: Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut. Electronic address: emily.finn@yale.edu.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Finn
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Xilin
authors.initials: X
authors.lastname: Shen
authors.affiliation: Yale Center for Dyslexia and Creativity, Yale University, New Haven, Connecticut.
authors.forename: John M
authors.initials: JM
authors.lastname: Holahan
authors.affiliation: Department of Biomedical Engineering, Yale University, New Haven, Connecticut.
authors.forename: Dustin
authors.initials: D
authors.lastname: Scheinost
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Lacadie
authors.affiliation: Department of Biomedical Engineering, Yale University, New Haven, Connecticut; Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Xenophon
authors.initials: X
authors.lastname: Papademetris
authors.affiliation: Yale Center for Dyslexia and Creativity, Yale University, New Haven, Connecticut.
authors.forename: Sally E
authors.initials: SE
authors.lastname: Shaywitz
authors.affiliation: Yale Center for Dyslexia and Creativity, Yale University, New Haven, Connecticut.
authors.forename: Bennett A
authors.initials: BA
authors.lastname: Shaywitz
authors.affiliation: Department of Biomedical Engineering, Yale University, New Haven, Connecticut; Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut; Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: R Todd
authors.initials: RT
authors.lastname: Constable
mesh_terms: D001921:Brain / Q000254:growth & development / Q000503:physiopathology*; D001931:Brain Mapping; D002648:Child; D004410:Dyslexia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000254:growth & development / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Brain networks; dyslexia; fMRI; functional connectivity; reading; visual attention