@misc{oai:repo.qst.go.jp:00071436,
 author = {Moriguchi, Sho and Yamada, Makiko and Suzuki, Masayuki and Suhara, Tetsuya and Moriguchi, Sho and Yamada, Makiko and Suhara, Tetsuya},
 month = {Mar},
 note = {Question: 
Majority of people believe they are better than others. This is a cognitive bias, called the superiority illusion. Our previous study revealed that the functional network responsible for superiority illusion was innervated by postsynaptic dopaminergic function in striatum (Yamada et al., 2013). In the current study, in order to deeply understand the role of dopamine on the superiority illusion, we investigated the relationship between presynaptic dopaminergic function and the superiority illusion.
Methods: 
Twelve healthy male volunteers were assessed with the superiority illusion task. Subjects underwent two positron emission tomography scans, using L-[β-11C]DOPA and [18F]FE-PE2I. Volumes of interest were defined for the putamen and caudate. The L-[β-11C]DOPA uptake rate reflects the dopaminergic synthesis capacity (kref), while non-displaceable binding potential (BPND) of [18F]FE-PE2I reflects the dopaminergic transporter (DAT) availability. We performed correlation analyses to compare the superiority illusion scores with kref and BPND .
Results: 
A significant negative correlation was observed between the BP values of [18F]FE-PE2I in the putamen and scores of the superiority illusion (r = -0.76, P = 0.0025), but not in the caudate. No significant correlation was found between the kref values of L-[β-11C]DOPA and scores on the superiority illusion tasks.
Conclusion: 
We found that DAT availability in the putamen is negatively associated with the superiority illusion. This suggests that the lower the DAT in the putamen, which may reflect the increased level of synaptic dopamine concentration, is associated with the higher superiority illusion. The current finding supports the role of dopamine on the superiority illusion, 30th International Congress of Clinical Neurophysiology (ICCN) of the International Federation of Clinical Neurophysiology (IFCN)},
 title = {Presynaptic dopaminergic function for the superiority illusion},
 year = {2014}
}