Cyclothymic temperament and glucose metabolism in the right superior parietal lobule.

Cyclothymic temperament possesses a central dimension that includes rapid fluctuations in mood and emotional instability, and it is regarded as a prodromal state of bipolar disorder. The aim of the present study is to explore the neural correlates of cyclothymic temperament. We used the data of 55 healthy participants in our previous study and analyzed the association between cyclothymic temperament scores rated by the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Autoquestionnaire (TEMPS-A) and the uptake of [18F]-FDG measured by positron emission tomography (PET). A whole brain analysis revealed a cluster of [18F]-FDG uptake significantly and positively associated with cyclothymic temperament scores, located in the right superior parietal lobule (SPL). Even after adjustment for relevant factors, there remained a significant cluster of [18F]-FDG uptake with cyclothymic temperament scores in the right SPL. In ROI analyses, there were similar significant peaks in the right SPL in association with cyclothymic temperament scores. These findings suggest that the right superior parietal lobule may be one of the neural correlates of cyclothymic temperament.