N400 and semantic categorization in schizophrenia.
The N400 component of event-related potentials (ERPs) was investigated in medicated schizophrenic patients and normal controls in a semantic categorization task. The subjects' task was to indicate whether pairs of words were semantically related or unrelated. The ERPs to the unrelated second words of the pairs contained a negative component, N400, which was reduced and delayed in the patients. However, inspection of individual subjects' data indicated that N400 was abnormal only in a subgroup of schizophrenics. Abnormalities in the amplitude of N400 suggest impairments in semantic expectancies, whereas abnormalities in the latency of N400 suggest a delay in information processing.
Grillon
C
C
Yale University School of Medicine, Department of Psychiatry, New Haven, CT 06510-3223.
Ameli
R
R
Glazer
W M
WM
D000328:Adult; D004569:Electroencephalography; D005071:Evoked Potentials; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D012559:Schizophrenia / Q000503:physiopathology*; D012564:Schizophrenic Language; D012660:Semantics