title: Deficient cortical face-sensitive N170 responses and basic visual processing in schizophrenia.
abstract: BACKGROUND
  Face detection, an ability to identify a visual stimulus as a face, is impaired in patients with schizophrenia. It is unclear whether impaired face processing in this psychiatric disorder results from face-specific domains or stems from more basic visual domains. In this study, we examined cortical face-sensitive N170 response in schizophrenia, taking into account deficient basic visual contrast processing.
  
  
  METHODS
  We equalized visual contrast signals among patients (n=20) and controls (n=20) and between face and tree images, based on their individual perceptual capacities (determined using psychophysical methods). We measured N170, a putative temporal marker of face processing, during face detection and tree detection.
  
  
  RESULTS
  In controls, N170 amplitudes were significantly greater for faces than trees across all three visual contrast levels tested (perceptual threshold, two times perceptual threshold and 100%). In patients, however, N170 amplitudes did not differ between faces and trees, indicating diminished face selectivity (indexed by the differential responses to face vs. tree).
  
  
  CONCLUSIONS
  These results indicate a lack of face-selectivity in temporal responses of brain machinery putatively responsible for face processing in schizophrenia. This neuroimaging finding suggests that face-specific processing is compromised in this psychiatric disorder.
authors.affiliation: McLean Hospital, Harvard Medical School, United States.
authors.forename: S
authors.initials: S
authors.lastname: Maher
authors.affiliation: McLean Hospital, Harvard Medical School, United States.
authors.forename: Y
authors.initials: Y
authors.lastname: Mashhoon
authors.affiliation: McLean Hospital, Harvard Medical School, United States.
authors.forename: T
authors.initials: T
authors.lastname: Ekstrom
authors.affiliation: McLean Hospital, Harvard Medical School, United States.
authors.forename: S
authors.initials: S
authors.lastname: Lukas
authors.affiliation: McLean Hospital, Harvard Medical School, United States. Electronic address: ychen@mclean.harvard.edu.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005071:Evoked Potentials; D000066499:Facial Recognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011569:Psychiatric Status Rating Scales; D011601:Psychophysics; D011618:Psychotic Disorders / Q000503:physiopathology*; D012559:Schizophrenia / Q000503:physiopathology*; D014787:Vision Tests
keywords: EEG; N170; Schizophrenia; face perception; visual detection