Increased NoGo-anteriorisation in first-episode schizophrenia patients during Continuous Performance Test.
OBJECTIVE
NoGo-stimuli during a Continuous Performance Test (CPT) activate prefrontal brain structures such as the anterior cingulate gyrus and lead to an anteriorisation of the positive electrical field of the NoGo-P300 relative to the Go-P300, so-called NoGo-anteriorisation (NGA). NGA during CPT is regarded as a neurophysiological standard index for cognitive response control. While it is known that patients with chronic schizophrenia exhibit a significant reduction in NGA, it is unclear whether this also occurs in patients undergoing their first-episode. Thus, the aim of the present study was to determine NGA in a group of patients with first-episode schizophrenia by utilizing a CPT paradigm.


METHODS
Eighteen patients with first-episode schizophrenia and 18 matched healthy subjects were investigated electrophysiologically during a cued CPT, and the parameters of the Go- and NoGo-P300 were determined using microstate analysis. Low resolution tomography analysis (LORETA) was used for source determination.


RESULTS
Due to a more posterior Go- and a more anterior NoGo-centroid, NGA was greater in patients than in healthy controls. LORETA indicated the same sources for both groups after Go-stimuli, but a more anterior source in patients after NoGo-stimuli. In patients P300-amplitude responses to both Go- and NoGo-stimuli were decreased, and P300-latency to NoGo-stimuli was increased. After the Go-stimuli false reactions and reaction times were increased in patients.


CONCLUSIONS
Attention was reduced in patients with first-episode schizophrenia, as indicated by more false reactions, prolongation of reaction time, P300-latencies and by a decrease in P300-amplitude. Significantly however, the NGA and prefrontal LORETA-sources indicate intact prefrontal brain structures in first-episode schizophrenia patients. Previously described changes in this indicator of prefrontal function may be related to a progressive decay in chronic schizophrenia.


CONCLUSIONS
The results support the idea of a possible new biological marker of first episode psychosis, which may be a useful parameter for the longitudinal measurement of changing prefrontal brain function in a single schizophrenia patient.
Kleinlogel
H
H
Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, University of Bern, Switzerland.
Strik
W
W
Begré
S
S
D000328:Adult; D015415:Biomarkers; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods*; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000033:anatomy & histology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D014054:Tomography
D015415:Biomarkers