Effects of the emotional connotations in words on the frontal areas--a spatially filtered MEG study.
The objective of this study was to elucidate how and where emotional connotations in words influenced linguistic processing in the language-related areas. We recorded neuromagnetic signals in nine right-handed and one left-handed healthy volunteers while they silently read emotional and emotionless words written in Japanese kanji characters, and investigated the distribution of the cerebral oscillatory changes using synthetic aperture magnetometry. Event-related desynchronizations (ERDs) in the beta-low gamma bands were observed in the anterior cingulate cortex (ACC) that were specific to the reading of emotional words in seven of nine right-handers. Beta-low gamma band ERDs were also detected in the left inferior or middle frontal gyrus (IFG or MFG) in nine right-handers regardless of the tasks. The magnitude of the ERDs in the IFG or MFG was significantly greater during emotional-word reading than during emotionless-word reading in nine right-handers. Left-dominant ERDs in the beta and gamma bands were observed in the prefrontal cortex (PFC) when negative emotional words were read (i.e. sadness), while right-dominant ERDs were observed for positive emotional words (i.e. happiness) in seven of nine right-handers (p=0.012, corrected). In one left-hander, the ERD in the ACC and the greater ERD that occurred in the IFG that was specific to emotional-word reading were also observed, but their lateralities in the IFG and PFC were reversed. These results suggest that emotional connotations in words facilitated the ERDs in the frontal language-related areas, and that these facilitations might be modulated by emotional processing in the ACC. Furthermore, negative and positive emotional words may be processed by different mechanisms.
Hirata
Masayuki
M
Division of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. mhirata@nsurg.med.osaka-u.ac.jp
Koreeda
Syunsuke
S
Sakihara
Kotoe
K
Kato
Amami
A
Yoshimine
Toshiki
T
Yorifuji
Shiro
S
D000328:Adult; D000465:Algorithms; D003463:Cues; D004644:Emotions / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007802:Language; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D011578:Psycholinguistics; D011932:Reading