Brain Dysfunction during the Performance of Wisconsin Card Sorting Test in First-episode Schizophrenia Patients
SHU Chang;XIAO Ling;WANG He-sheng;WANG Hui-ling;WANG Gao-hua;Department of Psychiatry,Wuhan University,Renmin Hospital;
Objective:To explore the characteristics of cerebral activation during the performance of Wisconsin card sorting test(WCST) in newly-developed schizophrenic patients without drug therapy. Methods: Twenty healthy subjects(control group) and twenty schizophrenic patients(patients group) underwent functional MRI(fMRI) during the performance of WCST and Color card sorting test(CCST). The active volume of the interested brain areas were compared between the 2 groups. Results: The images subtracted the functional images of CCST from those of WCST in the control group suggested that activations were mainly localized in the bilateral frontal lobes, especially in the dorsolateral prefrontal cortices, posterior parietal cortices and anterior cingulate gyry. The performance of WCST in the schizophrenic group were significantly lower than that in the healthy group(P0.01). The patients showed less activations in the left dorsolateral prefrontal cortex, and left anterior cingulated, but more activations in the left posterior parietal cortex, relative to the controls(P0.01 or 0.05). Conclusion: The bilateral frontal lobes, especially the dorsolateral prefrontal cortices, anterior cingulate gyri and posterior parietal cortices are involved in higher cognitive components of performance of WCST. Schizophrenic patients have executive function disorder at the initial stage of the disease. Evidences from fMRI indicate that the brain areas of patients including the left dorsolateral prefrontal cortex and left anterior cingulate are hypoactivative and hypofunctional whereas the posterior parietal cortices are hyperactive. The dysfunction of the prefrontal cortices and anterior cingulate cortices may be associated with the executive function disorder in schizophrenia. The hyperactivity of the posterior parietal cortices may compensate the hypofrontality to certain degree.