Association between regional cerebral blood flow and eye-tracking performance and the Wisconsin Card Sorting Test in schizophrenics: a single photon emission computed tomography study.

The objectives of this study were (1). to examine the changes in regional cerebral blood flow (rCBF) during Wisconsin Card Sorting Test (WCST) performance in two different eye-tracking groups; (2). to explore the relationship between eye-tracking movement and rCBF at rest; and (3). to estimate the association between WCST performance and rCBF in patients with schizophrenia. A total of 17 patients with schizophrenia were recruited. SPECT with Tc-99m HMPAO (Tc-99m hexamethylpropyleneamine oxime) was carried out while patients were performing the WCST and resting. Brodmann area 9 of the prefrontal cortex, a part of the dorsal lateral prefrontal cortex (DLPFC), was less activated during performance of the WCST in poor trackers (relative to good trackers). The eye pursuit tracking error measure in schizophrenic patients was negatively associated with decreases in rCBF in the middle temporal area, superior parietal lobule, thalami, and caudate nuclei. The rCBF increased significantly in the superior temporal gyri, inferior parietal lobe, and some frontal regions during WCST performance; however, this was not the case in the DLPFC. Additionally, significant correlations were found between WCST scores and rCBF during WCST performance in the prefrontal lobes, and in thalamic and cerebellar regions. Our findings suggest that the rCBF changes during WCST performance may be distinctive in different eye-tracking groups. Our results confirm the hypothesis that the middle temporal area, superior parietal lobule, thalami, and caudate nuclei-mainly parts of the oculomotor circuit-are involved in eye pursuit tracking. Surprisingly, no significant association was found in the frontal eye field. Although the frontal lobe plays a significant role in WCST performance, our findings demonstrate that WCST performance is widely involved with other regions in patients with schizophrenia.