title: Cortical contributions to impaired contour integration in schizophrenia.
abstract: OBJECTIVE
  Visual perceptual organization impairments in schizophrenia (SCZ) are well established, but their neurobiological bases are not. The current study used the previously validated Jittered Orientation Visual Integration (JOVI) task, along with fMRI, to examine the neural basis of contour integration (CI), and its impairment in SCZ. CI is an aspect of perceptual organization in which multiple distinct oriented elements are grouped into a single continuous boundary or shape.
  
  
  METHODS
  On the JOVI, five levels of orientational jitter were added to non-contiguous closed contour elements embedded in background noise to progressively increase the difficulty in perceiving contour elements as left- or right-pointing ovals. Multi-site fMRI data were analyzed for 56 healthy control subjects and 47 people with SCZ.
  
  
  RESULTS
  SCZ patients demonstrated poorer CI, and this was associated with increased activation in regions involved in global shape processing and visual attention, namely the lateral occipital complex and superior parietal lobules. There were no brain regions where controls demonstrated more activation than patients.
  
  
  CONCLUSIONS
  CI impairment in this sample of outpatients with SCZ was related to excessive activation in regions associated with object processing and allocation of visual-spatial attention. There was no evidence for basic impairments in contour element linking in the fMRI data. The latter may be limited to poor outcome patients, where more extensive structural and functional changes in the occipital lobe have been observed.
authors.affiliation: Rutgers, The State University of New Jersey, United States. Electronic address: steven.silverstein@rutgers.edu.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Silverstein
authors.affiliation: Washington University in St. Louis, United States.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Harms
authors.affiliation: University of California at Davis, United States.
authors.forename: Cameron S
authors.initials: CS
authors.lastname: Carter
authors.affiliation: University of Maryland, Maryland Psychiatric Research Center, United States.
authors.forename: James M
authors.initials: JM
authors.lastname: Gold
authors.affiliation: Rutgers, The State University of New Jersey, United States.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Keane
authors.affiliation: University of Minnesota, United States.
authors.forename: Angus
authors.initials: A
authors.lastname: MacDonald
authors.affiliation: University of California at Davis, United States.
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Ragland
authors.affiliation: Washington University in St. Louis, United States.
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Barch
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D005556:Form Perception / Q000502:physiology*; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009778:Occipital Lobe / Q000503:physiopathology; D010296:Parietal Lobe / Q000503:physiopathology; D012559:Schizophrenia / Q000503:physiopathology*
keywords: Contour integration; Lateral occipital complex; Perception; Perceptual organization; Schizophrenia; Vision; fMRI