title: Spatio-temporal EEG waves in first episode schizophrenia.
abstract: OBJECTIVE
  Schizophrenia is characterized by a deficit in context processing, with physiological correlates of hypofrontality and reduced amplitude P3b event-related potentials. We hypothesized an additional physiological correlate: differences in the spatio-temporal dynamics of cortical activity along the anterior-posterior axis of the scalp.
  
  
  METHODS
  This study assessed latency topographies of spatio-temporal waves under task conditions that elicit the P3b. EEG was recorded during separate auditory and visual tasks. Event-related spatio-temporal waves were quantified from scalp EEG of subjects with first episode schizophrenia (FES) and matched controls.
  
  
  RESULTS
  The P3b-related task conditions elicited a peak in spatio-temporal waves in the delta band at a similar latency to the P3b event-related potential. Subjects with FES had fewer episodes of anterior to posterior waves in the 2-4 Hz band compared to controls. Within the FES group, a tendency for fewer episodes of anterior to posterior waves was associated with high Psychomotor Poverty symptom factor scores.
  
  
  CONCLUSIONS
  Subjects with FES had altered global EEG dynamics along the anterior-posterior axis during task conditions involving context update.
  
  
  CONCLUSIONS
  The directional nature of this finding and its association with Psychomotor Poverty suggest this result is related to findings of hypofrontality in schizophrenia.
authors: Laboratory for Perceptual Dynamics, RIKEN Brain Science Institute, Japan. dalex@brain.riken.jp
authors: David M
authors: DM
authors: Alexander
authors: Gary J
authors: GJ
authors: Flynn
authors: Wilson
authors: W
authors: Wong
authors: Thomas J
authors: TJ
authors: Whitford
authors: Anthony W F
authors: AW
authors: Harris
authors: Cherrie A
authors: CA
authors: Galletly
authors: Steven M
authors: SM
authors: Silverstein
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D003627:Data Interpretation, Statistical; D003700:Delta Rhythm; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D055815:Young Adult