Task instructions modulate neural responses to fearful facial expressions.
BACKGROUND
The amygdala, hippocampus, ventral, and dorsal prefrontal cortices have been demonstrated to be involved in the response to fearful facial expressions. Little is known, however, about the effect of task instructions upon the intensity of responses within these regions to fear-inducing stimuli.


METHODS
Using functional magnetic resonance imaging, we examined neural responses to alternating, 30-sec blocks of fearful and neutral expressions in nine right-handed male volunteers during three different 5-min conditions: 1) passive viewing; 2) performance of a gender-decision task, with no explicit judgment of facial emotion; 3) performance of an emotionality judgment task - an explicitly emotional task.


RESULTS
There was a significant effect of task upon activation within the left hippocampus and the left inferior occipital gyrus, and upon the magnitude of response within the left hippocampus, with maximal activation in these regions occurring during passive viewing, and minimal during performance of the explicit task. Performance of the gender-decision and explicit tasks, but not passive viewing, was also associated with activation within ventral frontal cortex.


CONCLUSIONS
Neural responses to fearful facial expressions are modulated by task instructions.
Lange
Kezia
K
Institute of Psychiatry, London, United Kingdom.
Williams
Leanne M
LM
Young
Andrew W
AW
Bullmore
Edward T
ET
Brammer
Michael J
MJ
Williams
Steven C R
SC
Gray
Jeffrey A
JA
Phillips
Mary L
ML
D000679:Amygdala / Q000502:physiology; D001143:Arousal / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D004292:Dominance, Cerebral / Q000502:physiology; D017352:Echo-Planar Imaging; D005149:Facial Expression; D005239:Fear / Q000502:physiology*; D006179:Gyrus Cinguli / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D007089:Image Enhancement; D010101:Oxygen Consumption / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology; D011340:Problem Solving / Q000502:physiology; D012718:Set, Psychology; D013702:Temporal Lobe / Q000502:physiology