title: Patients with schizophrenia demonstrate reduced cortical sensitivity to auditory oddball regularities.
abstract: BACKGROUND
  Individuals with schizophrenia demonstrate deficits in context processing. These deficits can be characterized by examining the influence of auditory context on ERP responses to rare target tones. Previous studies demonstrate that target ERP deficits in schizophrenia depend on the number of non-targets that precede the target ERP. Our goal was to extend these findings by examining whether patients with schizophrenia demonstrate a reduced sensitivity to subtle differences in the auditory context preceding rare target stimuli, as quantified by Itti and Baldi's Bayesian prediction error model.
  
  
  METHODS
  Cortical responses to auditory oddball tones were measured within 59 individuals with schizophrenia (SZ) and 59 controls (HC). Individual trial amplitudes were estimated by conducting group ICA on the EEG time series and analyzing the reconstructed individual temporal sources. We quantified the auditory context of target tones using the Bayesian prediction error model and determined whether ERP amplitudes to tones were sensitive to this measure of context, or the number of preceding non-targets directly, within HC and SZ.
  
  
  RESULTS
  Individuals with schizophrenia show a significant reduction in ERP response amplitudes to targets approximately 244-412 ms following target onsets. Individual amplitudes within this window showed significantly greater sensitivity to the modeled prediction error within the controls than in individuals with schizophrenia. These differences approached significance when examining differences in amplitudes as a function of the number of preceding non-targets.
  
  
  CONCLUSIONS
  These findings further clarify differences in HC and SZ with regard to their attentional and perceptual sensitivity to subtle environmental regularities.
authors.affiliation: The Mind Research Network, Albuquerque, NM, USA. Electronic address: dbridwell@mrn.org.
authors.forename: David A
authors.initials: DA
authors.lastname: Bridwell
authors.affiliation: The Mind Research Network, Albuquerque, NM, USA; Department of Psychology and Neuroscience, University of New Mexico, Albuquerque, NM, USA.
authors.forename: Kent A
authors.initials: KA
authors.lastname: Kiehl
authors.affiliation: Olin Neuropsychiatry Research Center, Hartford, CT, USA; Department of Psychiatry and Neurobiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Godfrey D
authors.initials: GD
authors.lastname: Pearlson
authors.affiliation: The Mind Research Network, Albuquerque, NM, USA; Department of Psychiatry and Neurobiology, Yale University School of Medicine, New Haven, CT, USA; Department of ECE, University of New Mexico, Albuquerque, NM, USA.
authors.forename: Vince D
authors.initials: VD
authors.lastname: Calhoun
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001499:Bayes Theorem; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D009483:Neuropsychological Tests; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology
keywords: Acoustic regularities; Auditory oddball; Bayesian prediction error; Context processing; Perceptual organization; Schizophrenia