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Abstract:
Previous neuroimaging studies have associated face perception
with activity in the fusiform gyrus (FG), and perception of eye
movement with activity in the superior temporal sulcus (STS). We
tested whether selective attention to face identity differentially
augmented activity in FG, and whether selective attention to eye
gaze differentially augmented activity in STS. Hemodynamic changes
were measured in four subjects using BOLD-EPI fMRI during
performance of one-back repetition detection of face identity and
eye gaze. In the identity task, subjects indicated whether each
picture was of the same individual shown in the previous trial. In
the eye-gaze task, subjects indicated whether eye gaze direction on
a face matched that seen in the previous trial. We found bilateral
activation of STS, FG, and intraparietal sulcus (IPS) in all four
subjects. FG consistently responded more during selective attention
to identity (p<0.0005), whereas both STS and IPS responded more
during selective attention to eye gaze (p<0.0001 and p<0.05,
respectively). These results suggest that there is a distributed
system of regions that is engaged by different aspects of face
processing. FG activity appears to be associated with perception of
identity, not just with perception of generic facial configuration.
STS, on the other hand, is associated with perception of gaze
direction. Preferential activation of IPS during perception of eye
gaze may indicate recruitment of spatial attention systems to draw
attention to the direction of another person's gaze.
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