Automatic and intentional brain responses during evaluation of face approachability: correlations with trait anxiety.
BACKGROUND
The judgment of the approachability of others based on their facial appearance often precedes social interaction. Whether we ultimately approach or avoid others may depend on such judgments.


METHODS
We used functional magnetic resonance imaging to determine the neural basis for such approachability judgments and the relationship between these judgments and trait anxiety. Participants viewed ambiguous (i.e. neutral) or relatively unambiguous (i.e. angry, happy) faces, assessing either the approachability or the sex of the person depicted.


RESULTS
Neutral faces elicited more inconsistent responses within participants only during approachability judgment, suggesting ambiguous property as signals. The contrast pertaining to the interaction between task and face valence demonstrated activation in several areas, such that the left amygdala and medial, middle and inferior frontal gyri were responsive to angry faces when subjects were asked to recognize the sex (implicit task) and to neutral faces when required to discern the approachability (explicit task). Moreover, the blood oxygenation level-dependent change within the left amygdala in response to neutral faces during the judgment of approachability was positively correlated with participant trait anxiety.


CONCLUSIONS
These findings extend a proposed model of social cognition by highlighting the functional engagement of the amygdala in approachability judgments, which underlie an individual's sensitivity to ambiguous sources of probable threat.
Department of Psychiatry and Neurosciences, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Shigeru
S
Toki
Yasumasa
Y
Okamoto
Keiichi
K
Onoda
Akiko
A
Kinoshita
Kazuhiro
K
Shishida
Akihiko
A
Machino
Takuji
T
Fukumoto
Hidehisa
H
Yamashita
Hiroshi
H
Yoshida
Shigeto
S
Yamawaki
D000328:Adult; D000679:Amygdala / Q000502:physiology*; D001007:Anxiety / Q000503:physiopathology*; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D005149:Facial Expression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012919:Social Behavior; D055815:Young Adult