Association between affective temperaments and regional gray matter volume in healthy subjects.
BACKGROUND
Affective temperaments such as cyclothymic and hyperthymic temperaments have been regarded as potential antecedents of bipolar disorder but the neural substrates underlying these temperaments have not been identified. The aim of this study is to determine whether these temperaments are associated with specific neural substrates in regional brain morphology in healthy subjects.


METHODS
We conducted a cross-sectional neuroimaging study of 60 healthy subjects (30 males and 30 females) with affective temperaments. All participants underwent the Mini-International Neuropsychiatric Interview (MINI) to screen for the past and present psychiatric disorder. The scores of cyclothymic and hyperthymic temperaments were measured by the Temperament Scale of Memphis, Pisa, Paris and San Diego-Autoquestionnaire. We analyzed the association between voxel-based morphometry of the brain and these affective temperaments.


RESULTS
Subjects classified as having high cyclothymic scores had a significantly larger gray matter volume of the left medial frontal gyrus (MFG) than low cyclothymic subjects. High hyperthymic males also had significantly larger gray matter volume of the left MFG than low hyperthymic males, but there was no difference in females. Subjects with both high cyclothymic and high hyperthymic temperaments demonstrated significantly larger gray matter volume of the left MFG than their counterparts. Region of interest analysis revealed that peaks of these clusters showed a significant positive correlation of the regional volume with temperament scores.


CONCLUSIONS
The subjects were relatively young and the number was relatively small. Due to the nature of a cross-sectional research design, we could not determine the causal relationship between temperament and the volume changes.


CONCLUSIONS
These findings suggest that cyclothymic and hyperthymic temperaments in healthy subjects may have their morphological basis in the left MFG.
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan. Electronic address: k-hatano@oita-u.ac.jp.
Koji
K
Hatano
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Takeshi
T
Terao
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Nobuhiko
N
Hoaki
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Kentaro
K
Kohno
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Yasuo
Y
Araki
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Yoshinori
Y
Mizokami
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Kensuke
K
Kodama
Department of Neuropsychiatry, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita Prefecture 8795593, Japan.
Mayu
M
Harada
Department of Neurosurgery, Oita University Faculty of Medicine, Oita, Japan.
Minoru
M
Fujiki
Department of Neurosurgery, Oita University Faculty of Medicine, Oita, Japan.
Tsuyoshi
T
Shimomura
Functional Architecture Imaging Unit, RIKEN Center for Life Science Technologies, Hyogo, Japan.
Takuya
T
Hayashi
D000328:Adult; D000339:Affect; D001921:Brain / Q000033:anatomy & histology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009929:Organ Size; D013694:Temperament; D055815:Young Adult
Cyclothymic temperament; Healthy subject; Hyperthymic temperament; Left medial frontal gyrus; VBM