title: Decreased spatial frequency sensitivities for processing faces in male patients with chronic schizophrenia.
abstract: OBJECTIVE
  Schizophrenia impairs early visual cognitive processing. Low and high spatial frequency (LSF, HSF) visual information are differentially processed in humans. We investigated whether electrophysiological abnormalities exist in visual processing for spatial frequency (SF)-filtered neutral/emotional faces in schizophrenics.
  
  
  METHODS
  Subjects consisted of 16 male chronic schizophrenics and 23 controls. Event-related potentials (ERPs) to SF-filtered (LSF or HSF) and unfiltered (broad SF; BSF) pictures of neutral, happy, and fearful faces were recorded at 20 scalp sites. The relationships between the P100 (P1)/N170 amplitudes and the Global Assessment of Functioning (GAF) scores in patients were also evaluated.
  
  
  RESULTS
  For the P1 amplitudes at O1/O2, controls exhibited a significant LSF>BSF difference, while schizophrenics showed no LSF>BSF difference. For the N170 amplitudes at T5/T6, controls revealed a significant HSF>BSF difference, while schizophrenics showed no such difference. For the P1 latencies, controls but not schizophrenics showed a significant difference (LSF>BSF=HSF). For the N170 latencies, no significant SF differentiation was found between the two groups. For both P1 and N170 amplitudes, no significant effects of facial expressions were observed in controls and patients regardless of SFs. There were significant negative correlations between the GAF scores and the N170 amplitudes to BSF faces in schizophrenics, but not for P1 amplitudes.
  
  
  CONCLUSIONS
  Schizophrenics showed abnormal P1 and N170 responses to SF changes in faces, thus indicating decreased SF sensitivities for processing of faces.
  
  
  CONCLUSIONS
  Abnormal early visual processing may underlie some of the deficits associated with face recognition in schizophrenia.
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Choji
authors.initials: C
authors.lastname: Obayashi
authors.forename: Taisuke
authors.initials: T
authors.lastname: Nakashima
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Onitsuka
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Maekawa
authors.forename: Yoji
authors.initials: Y
authors.lastname: Hirano
authors.forename: Shogo
authors.initials: S
authors.lastname: Hirano
authors.forename: Naoya
authors.initials: N
authors.lastname: Oribe
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kaneko
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Kanba
authors.forename: Shozo
authors.initials: S
authors.lastname: Tobimatsu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D005149:Facial Expression; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D013223:Statistics as Topic; D055815:Young Adult