Learning potential on the WCST in schizophrenia is related to the neuronal integrity of the anterior cingulate cortex as measured by proton magnetic resonance spectroscopy.
BACKGROUND
In recent years, schizophrenia has increasingly been recognized as a neurocognitive disorder, which has led to a growing literature on cognitive rehabilitation, and suggested several potential enhancements to cognitive function. For instance, it has been shown that executive functioning deficits as measured by the Wisconsin Card Sorting Test (WCST) can be modified in a subgroup of schizophrenic patients. The neurobiological basis of cognitive remediation has not been elucidated so far, although structural, functional and metabolic abnormalities of the prefrontal cortex have been associated with cognitive impairment.


METHODS
In this study, learning potential was investigated in 43 schizophrenic patients and 37 age- and education-matched healthy controls, using a dynamic version of the WCST, which integrates instructions and feedback into the testing procedure. Performance was related to cerebral metabolism, assessed by single-voxel proton magnetic resonance spectroscopy of the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC).


RESULTS
N-acetylaspartate (NAA), a marker of neuronal integrity, was significantly reduced in the DLPFC of schizophrenic patients as compared to the healthy control group. The level of NAA in the DLPFC positively correlated with performance in the dynamic WCST in healthy subjects, whereas in schizophrenic patients a significant correlation was observed between NAA and glutamate/glutamine in the ACC and learning potential.


CONCLUSIONS
These data imply a relationship between neuronal plasticity as assessed by learning potential and NAA levels of the prefrontal cortex in schizophrenic patients and healthy subjects, and suggest the involvement of differential neuronal networks in learning for schizophrenic patients compared to healthy controls.
Ohrmann
Patricia
P
Department of Psychiatry, University of Muenster, Germany. ohrmann@uni-muenster.de
Kugel
Harald
H
Bauer
Jochen
J
Siegmund
Ansgar
A
Kölkebeck
Katja
K
Suslow
Thomas
T
Wiedl
Karl H
KH
Rothermundt
Matthias
M
Arolt
Volker
V
Pedersen
Anya
A
D000328:Adult; D001076:Aptitude; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D003072:Cognition Disorders / Q000175:diagnosis*; D005260:Female; D007839:Functional Laterality; D006179:Gyrus Cinguli / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D011877:Radionuclide Imaging; D012559:Schizophrenia / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D012565:Schizophrenic Psychology
D001224:Aspartic Acid; C000179:N-acetylaspartate