title: Evidence for unaltered brain electrical topography during prefrontal response control in cycloid psychoses.
abstract: OBJECTIVE
  Prefrontal structures such as the anterior cingulate cortex (ACC) play a decisive role in processes of action monitoring and response control, functions often impaired in schizophrenia. Patients with cycloid psychoses exhibit some characteristic neurophysiological features not indicative of the cerebral hypofrontality observed in schizophrenia. This study aimed at examining if cycloid psychoses-unlike schizophrenias-involve a normal brain-electrical topography during a task demanding prefrontal response control.
  
  
  METHODS
  Thirty-seven patients with cycloid psychoses and 37 healthy controls were investigated electrophysiologically while performing a Continuous Performance Test (CPT). Topographical analyses were conducted to individually quantify the Nogo-anteriorisation (NGA) as a neurophysiological index of prefrontal response control.
  
  
  RESULTS
  The patients exhibited an unaltered topography with a mean NGA not significantly different from the controls. They did, however, differ from the control group regarding their Global Field Power (GFP), with a significantly reduced GFP (p<0.001) and decreased latencies (p<0.01) during Nogo trials. On a behavioral level, patients exhibited prolonged reaction times and an increased rate of omission errors.
  
  
  CONCLUSIONS
  The investigated patients showed an activation of specific (presumably frontal) brain areas during Nogo trials, resulting in a frontalisation of the brain-electrical field comparable to the control group. However, the strength of this activation was apparently reduced. The patients' unaltered topographical pattern contrasts with previous findings in schizophrenic patients and supports the hypothesis that cycloid psychoses entail less severe prefrontal deficits than schizophrenias, which might be an indication of different biological backgrounds for both groups of endogenous psychoses.
authors.affiliation: Laboratory for Psychophysiology and Functional Imaging, Department of Psychiatry and Psychotherapy, University Hospital of Wuerzburg Fuechsleinstrasse 15, 97080 Wuerzburg, Germany. aehlis@mail.uni-wuerzburg.de
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Ehlis
authors.forename: Jürgen
authors.initials: J
authors.lastname: Zielasek
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Herrmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Ringel
authors.forename: Christian
authors.initials: C
authors.lastname: Jacob
authors.forename: Annika
authors.initials: A
authors.lastname: Wagener
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Fallgatter
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D003657:Decision Making / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance / Q000502:physiology; D011618:Psychotic Disorders / Q000145:classification / Q000503:physiopathology*; D011930:Reaction Time; D012559:Schizophrenia / Q000503:physiopathology; D012720:Severity of Illness Index