- 作者：Mayu Harada ; Takeshi Terao ; Koji Hatano ; Kentaro Kohno ; Yasuo Araki ; Yoshinori Mizokami ; Kensuke Kodama ; Nobuhiko Hoaki ; Miyano Arasaki ; Tsuyoshi Shimomura ; Minoru Fujiki ; Takanori Kochiyama
- 关键词：Hyperthymic temperament ; Brightness preference ; fMRI ; Left inferior orbitofrontal cortex
- 刊名：Journal of Affective Disorders
- 出版年：2013
- 出版时间：November, 2013
- 年：2013
- 卷：151
- 期：2
- 页码：763-768
- 全文大小：2958 K
Background
Hyperthymic temperament has been generally accepted as one of premorbid temperament of bipolar disorders. Although several studies indicate that subjects with hyperthymic temperament receive more illuminance, our recent study suggests that the threshold of brightness and darkness judgment is not different between more and less hyperthymic subjects, and that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which has been reported to be associated with bipolar disorder. Therefore, at the next stage, it can be hypothesized that hyperthymic subjects may prefer brightness (i.e., heliotropism) and thereby seek illuminance, and that percent signal changes of left inferior orbitofrontal cortex during the preference task may be associated with hyperthymic temperament scores.Methods
We compared brightness preference and un-preference between more and less hyperthymic subjects, and investigated percent signal changes of left inferior orbitofrontal cortex during brightness preference judgment, brightness un-preference judgment, and control task by using functional Magnetic Resonance Imaging (fMRI).
Results
There were significant differences in brightness preference judgment and un-preference judgment, showing that more hyperthymic subjects preferred brighter illuminace levels and un-preferred darker illuminance levels than less hyperthymic subjects. Moreover, fMRI signal changes of left inferior orbitofrontal cortex was significantly and negatively associated with hyperthymic temperament scores.
Limitations
It is unknown why left but not right inferior orbitofrontal cortex was associated with hyperthymic temperament scores.
Conclusions
The present findings suggest that more hyperthymic subjects may prefer brightness and un-prefer darkness than less hyperthymic subjects (i.e., heliotropism), and reconfirm that hyperthymic temperament may be associated with left inferior orbitofrontal cortex, which have been reported to be associated with bipolar disorders.