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Abstract:
Cross-race (CR) faces have been found to be faster classified
by race than same race (SR) faces. The purpose of the present study
was to investigate the spatiotemporal dynamics of the brain
electrical activity of this phenomenon. 64-channel surface
event-related potentials (ERPs) were recorded in twelve Caucasian
right-handed subjects classifying Caucasian and Asian faces by
race. ERP mapping using adaptive segmentation procedure was
combined with classical waveforms analysis. For both kind of faces,
eight stable ERP map topographies were found. These maps occurred
in the same order and strength (Global Field Power - GFP). Waveform
analysis showed no difference for the P1 and face specific N170
components. However, two segment maps following the N170 map
appeared faster for the CR condition. In the first, the POZ
electrode with a positivity and the GFP peaked at 240ms for CR,
14ms earlier than SR. The second segment map best fitted at 300ms
for CR, 26ms earlier than SR. These results suggest that face
classification by race involves the same functional pathways
regardless of race. CR classification advantage appears after the
structural encoding stage (N170). CR classification takes less
processing time in modules that may reflect activation of visually
derived semantic information from faces.
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