Is there a cortical blood flow redistribution pattern related with perseverative error in schizophrenia?

BACKGROUND: We studied relative cortical blood flow (relCBF) patterns associated to correct performance (CP) and perseverative error (PE) during Wisconsin Card Sorting Test (WCST) execution, in controls and patients with schizophrenia.

SUBJECTS AND METHODS: relCBF (regional cortical blood flow (rCBF) / whole cortex blood flow) of 10 well defined cortical regions was measured in 18 patients with schizophrenia and 13 healthy controls by a Technetium - 99 - HMPAO - SPECT, at rest and while they performed WCST.

RESULTS: Patients made significantly more PE than controls during WCST performance. In patients, we found a significant correlation between PE and relCBF in right occipital cortex. In controls, we found a significant correlation between CP and relCBF of several cortical regions during WCST execution: left orbitofrontal cortex and left global frontal cortex positively and parietal bilateral cortex negatively. PE was inversely correlated with relCBF in left temporal cortex.

CONCLUSIONS: Successful WCST performance is associated to a high left frontal activity in controls but not in patients. The severity of PE during WCST performance is associated to a low left frontal-temporal activity in controls and to a high right parietal-occipital activity in schizophrenia. This may represent a cortical activity redistribution pattern related to perseveration in schizophrenia.