title: Hyperthymic temperament and brightness preference in healthy subjects: further evidence for involvement of left inferior orbitofrontal cortex in hyperthymic temperament.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Harada
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan. Electronic address: terao@oita-u.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Terao
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Hatano
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kohno
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Araki
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Mizokami
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kodama
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hoaki
authors.affiliation: Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita 879-5593, Japan.
authors.forename: Miyano
authors.initials: M
authors.lastname: Arasaki
authors.affiliation: Department of Neurosurgery, Oita University Faculty of Medicine, Oita, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shimomura
authors.affiliation: Department of Neurosurgery, Oita University Faculty of Medicine, Oita, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Fujiki
authors.affiliation: ATR Promotions, Brain Activity Imaging Center, Kyoto, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kochiyama
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008027:Light; D008279:Magnetic Resonance Imaging; D008297:Male; D057240:Patient Preference; D013694:Temperament / Q000502:physiology*; D055815:Young Adult
keywords: Brightness preference; Hyperthymic temperament; Left inferior orbitofrontal cortex; fMRI