title: Dissection of early bottom-up and top-down deficits during visual attention in schizophrenia.
abstract: OBJECTIVE
  To characterize the interplay of bottom-up and top-down processing deficits of the early visual ERP component N1 in schizophrenia.
  
  
  METHODS
  Thirty-three schizophrenic patients and 61 healthy controls underwent a visual selective attention paradigm while 32-channel electroencephalogram was recorded. Visual N1 responses were calculated and source localization was applied.
  
  
  RESULTS
  Significant reductions of the cue N1 as well as the target N1 components were found in schizophrenia patients. Linear regression slopes for the cue N1 and for the cue-locked target N1 indicated significantly reduced early bottom-up and top-down modulation in patients relative to controls. Source analyses indicated that bottom-up as well as top-down N1 deficits in schizophrenia are associated with partially overlapping current density deficits in posterior cortex areas. Differential functional deficits were observed in right parietal lobe during bottom-up processing and in anterior cingulate cortex during top-down attention.
  
  
  CONCLUSIONS
  The results provide evidence for both early visual bottom-up and top-down deficits in schizophrenia and illustrate how disturbances in these processing streams converge on the visual N1 amplitude.
  
  
  CONCLUSIONS
  Visual top-down disturbances in schizophrenia appear to be confounded by visual bottom-up deficits.
authors.affiliation: Department of Psychiatry and Psychotherapy, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany. andres.neuhaus@charite.de
authors.forename: Andres H
authors.initials: AH
authors.lastname: Neuhaus
authors.forename: Christine
authors.initials: C
authors.lastname: Karl
authors.forename: Eric
authors.initials: E
authors.lastname: Hahn
authors.forename: Niklas R
authors.initials: NR
authors.lastname: Trempler
authors.forename: Carolin
authors.initials: C
authors.lastname: Opgen-Rhein
authors.forename: Carsten
authors.initials: C
authors.lastname: Urbanek
authors.forename: Constanze
authors.initials: C
authors.lastname: Hahn
authors.forename: Thi Minh Tam
authors.initials: TM
authors.lastname: Ta
authors.forename: Michael
authors.initials: M
authors.lastname: Dettling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001288:Attention / Q000502:physiology*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards; D010468:Perceptual Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012559:Schizophrenia / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult