Decreased spatial frequency sensitivities for processing faces in male patients with chronic schizophrenia.
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.
Obayashi
Choji
C
Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.
Nakashima
Taisuke
T
Onitsuka
Toshiaki
T
Maekawa
Toshihiko
T
Hirano
Yoji
Y
Hirano
Shogo
S
Oribe
Naoya
N
Kaneko
Kunihiko
K
Kanba
Shigenobu
S
Tobimatsu
Shozo
S
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