Dissociation of face-selective cortical responses by attention.
We studied attentional modulation of cortical processing of faces and houses with functional MRI and magnetoencephalography (MEG). MEG detected an early, transient face-selective response. Directing attention to houses in "double-exposure" pictures of superimposed faces and houses strongly suppressed the characteristic, face-selective functional MRI response in the fusiform gyrus. By contrast, attention had no effect on the M170, the early, face-selective response detected with MEG. Late (>190 ms) category-related MEG responses elicited by faces and houses, however, were strongly modulated by attention. These results indicate that hemodynamic and electrophysiological measures of face-selective cortical processing complement each other. The hemodynamic signals reflect primarily late responses that can be modulated by feedback connections. By contrast, the early, face-specific M170 that was not modulated by attention likely reflects a rapid, feed-forward phase of face-selective processing.
Furey
Maura L
ML
Laboratory of Brain and Cognition and Mood and Anxiety Disorders Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA. mfurey@mail.nih.gov
Tanskanen
Topi
T
Beauchamp
Michael S
MS
Avikainen
Sari
S
Uutela
Kimmo
K
Hari
Riitta
R
Haxby
James V
JV
D001288:Attention; D001931:Brain Mapping; D003627:Data Interpretation, Statistical; D004574:Electromagnetic Fields; D005074:Evoked Potentials, Visual; D005145:Face; D005149:Facial Expression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000473:pathology; D013997:Time Factors; D014796:Visual Perception