@misc{oai:repo.qst.go.jp:00071623,
 author = {Takahata, Keisuke and Suhara, Tetsuya and Yamada, Makiko and Takahata, Keisuke and Suhara, Tetsuya and Yamada, Makiko},
 month = {Mar},
 note = {Question: Fluency tasks have been widely used to evaluate executive functions mainly implemented in the frontal lobes. Meanwhile, a recent PET study showed that divergent thinking, which was associated with fluency tasks, was related to dopamine D2 receptor densities in the thalamus, but the role of D2 in the frontal lobes remains unclear. In the current study, we were interested to understand how dopaminergic neurotransmission in the frontal lobes and thalamus were associated to fluency performance, in relation with a specific psychiatric symptom of depersonalization. 
Methods: We performed PET studies on 24 healthy male subjects. Extrastriatal dopamine D2 receptor bindings were measured by 60 min PET scans using [11C]FLB457). For each PET scan, BPND were calculated using SRTM using the cerebellum as a reference region. Outside the scanner, all participants performed ideational and word fluency tasks and 15 subjects fulfilled Cambridge Depersonalization Scale (CDS).
Results: Voxel-by-voxel analysis revealed that dopamine D2 receptor binding potentials (D2 BPND) in the right prefrontal cortex were negatively correlated with performance of idea fluency task, but no region was found for word fluency. We conducted an additional ROI analysis for thalamus using thalamic connectivity atlas to investigate whether a specific thalamo-cortical connection played a role in idea fluency. Negative correlation between D2 BPND and idea fluency performance was found in the thalamic region that had projections onto prefrontal cortex. We further revealed performance of ideational fluency was positively correlated with CDS scores.
Conclusions: Tendency of depersonalization scale was related to idea fluency, which was associated with dopaminergic transmission in the prefrontal cortex and its anatomically connected region in the thalamus., 30th International Congress  of Clinical Neurophysiology (ICCN) of the IFCN},
 title = {Association among extrastriatal dopamine D2 receptor binding, idea fluency and depersonalization: A positron emission tomography study},
 year = {2014}
}