Face-identity change activation outside the face system: "release from adaptation" may not always indicate neuronal selectivity.
Face recognition is a complex cognitive process that requires distinguishable neuronal representations of individual faces. Previous functional magnetic resonance imaging (fMRI) studies using the "fMRI-adaptation" technique have suggested the existence of face-identity representations in face-selective regions, including the fusiform face area (FFA). Here, we present face-identity adaptation findings that are not well explained in terms of face-identity representations. We performed blood-oxygen level-dependent (BOLD) fMRI measurements, while participants viewed familiar faces that were shown repeatedly throughout the experiment. We found decreased activation for repeated faces in face-selective regions, as expected based on previous studies. However, we found similar effects in regions that are not face-selective, including the parahippocampal place area (PPA) and early visual cortex (EVC). These effects were present for exact-image (same view and lighting) as well as different-image (different view and/or lighting) repetition, but more widespread for exact-image repetition. Given the known functional properties of PPA and EVC, it appears unlikely that they contain domain-specific face-identity representations. Alternative interpretations include general attentional effects and carryover of activation from connected regions. These results remind us that fMRI stimulus-change effects can have a range of causes and do not provide conclusive evidence for a neuronal representation of the changed stimulus property.
Mur
Marieke
M
Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA. marieke.mur@maastrichtuniversity.nl
Ruff
Douglas A
DA
Bodurka
Jerzy
J
Bandettini
Peter A
PA
Kriegeskorte
Nikolaus
N
D000222:Adaptation, Physiological; D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology*; D005145:Face / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D021641:Recognition, Psychology / Q000502:physiology*
D010100:Oxygen