Influence of vigilance and learning on prefrontal activation in schizophrenia.
BACKGROUND
Executive functions, which are neuroanatomically associated with the frontal lobe, are known to be impaired in schizophrenia. It is, however, still unclear whether the underlying functional disturbance is due to a hyper- or a hypoactivation of the dorsolateral prefrontal cortex (DLPFC) or neither.


METHODS
To address this question, we examined the brain activation of 21 schizophrenic patients on atypical antipsychotic medication and 21 healthy control subjects during a mental maze task by means of fMRI.


RESULTS
We found no significant overall difference in cerebral activation between the groups, but differences in the change in DLPFC activation from the first to the second half of the experiment. In the maze compared to the control task, there was a decrease in activation in the DLPFC in the patients and an almost significant increase in the controls. The change in activation in the patient group correlated with a change in subjective sleepiness, while the increase in activation in the controls could be attributed to learning processes.


CONCLUSIONS
We hypothesized that differential temporal influences on brain activation could lead to either hyper- or hypoactivation of the DLPFC in schizophrenia.
Esslinger
Christine
C
Center for Psychiatry, Justus Liebig University School of Medicine, Giessen, Germany. christine.esslinger@zi-mannheim.de
Gruppe
Harald
H
Danos
Peter
P
Lis
Stefanie
S
Broll
Jochen
J
Wiltink
Joerg
J
Gallhofer
Bernd
B
Kirsch
Peter
P
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001143:Arousal / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007858:Learning / Q000187:drug effects / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017397:Prefrontal Cortex / Q000098:blood supply / Q000187:drug effects / Q000503:physiopathology*; D012559:Schizophrenia / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D013647:Task Performance and Analysis
D014150:Antipsychotic Agents; D010100:Oxygen