title: Visual attention circuitry in schizophrenia investigated with oddball event-related functional magnetic resonance imaging.
abstract: OBJECTIVE
  Schizophrenia patients have problems directing attention. Sustained attention requires ensuring that brain resources are focused on a selected target (top-down task) while ignoring irrelevant distractors (bottom-up interference). Whether patients have too little ability to focus or too much interference from distraction has not been clarified. The oddball paradigm embeds infrequent targets and distractors into the stimulus train, and schizophrenia deficits have been linked to diminished responses to both. Cerebral activity underlying abnormal attention can be examined with event-related functional magnetic resonance imaging.
  
  
  METHODS
  A visual oddball task was presented to 22 patients with schizophrenia and 28 comparison subjects. Statistical probability maps reflecting blood-oxygenation-level-dependent changes were generated for infrequent targets and novel distractors relative to frequent standard stimuli. Activation was related to performance and symptoms.
  
  
  RESULTS
  Activation specific to targets and distractors was associated with faster performance. For targets, patients had diminished activation in superior temporal and frontal gyri, cingulate, thalamus, and basal ganglia. They had increased activation in right insula, mid-frontal gyrus, posterior cingulate, and left inferior parietal lobule. For distractors, patients showed less activation in occipital regions and left inferior parietal lobule but increased activation in parietal-occipital, right mid-frontal, and left inferior frontal gyri. Abnormal activation correlated with positive and negative symptoms.
  
  
  CONCLUSIONS
  Abnormal activation in schizophrenia in response to attentional demands reflects both insufficient recruitment of brain systems required for target detection and overcommitment of resources for processing irrelevant distractors. Schizophrenia patients appear to have an inability both to focus on targets and ignore distraction.
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. raquel@bbl.med.upenn.edu
authors.forename: Raquel E
authors.initials: RE
authors.lastname: Gur
authors.forename: Bruce I
authors.initials: BI
authors.lastname: Turetsky
authors.forename: James
authors.initials: J
authors.lastname: Loughead
authors.forename: Wendy
authors.initials: W
authors.lastname: Snyder
authors.forename: Christian
authors.initials: C
authors.lastname: Kohler
authors.forename: Mark
authors.initials: M
authors.lastname: Elliott
authors.forename: Ramapriyan
authors.initials: R
authors.lastname: Pratiwadi
authors.forename: J Daniel
authors.initials: JD
authors.lastname: Ragland
authors.forename: Warren B
authors.initials: WB
authors.lastname: Bilker
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Siegel
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Kanes
authors.forename: Steven E
authors.initials: SE
authors.lastname: Arnold
authors.forename: Ruben C
authors.initials: RC
authors.lastname: Gur
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D014795:Visual Pathways / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology*
chemical_list: D010100:Oxygen