title: Neuroanatomic correlates of the feature-salience hierarchy in face processing: an fMRI -adaptation study.
abstract: Previous fMRI studies suggest that faces are represented holistically in human face processing regions. On the other hand, behavioral studies have also shown that some facial features are more salient than others for face recognition: the neural basis of this feature-salience hierarchy is not known. We used fMRI-adaptation together with a behavioral discrimination task and an ideal observer analysis to ask (1) whether different face parts contribute different amounts to the neural signal in face responsive regions, and (2) whether this response correlates more with the behavioral performance of human subjects or with the physical properties of the face stimuli. Twenty-three subjects performed a same/different discrimination experiment to characterize their ability to detect changes to different face parts. The same subjects underwent an fMRI-adaptation study, in which limited portions of the faces were repeated or changed between alternating stimuli. The behavioral study showed high efficiency in identity discrimination when the whole face, top half, or eyes changed, and low efficiency when the bottom half, nose, or mouth changed. During fMRI, there was a release of adaptation in the right and left fusiform face area (FFA) with changes to the whole face, top face-half, or the eyes. Changes to the bottom half, nose or mouth did not result in a significant release of adaptation in the right FFA, although bottom-half changes resulted in a release of adaptation in the left FFA. Adaptation in the right and left FFA and the right pSTS was correlated with human perceptual efficiency but not with ideal observer measures of the physical image differences between face parts. The feature-salience hierarchy of human face perception is therefore reflected in the activity in the right and left FFA and right pSTS, further supporting the key role of these structures in our perceptual experience of faces.
authors.affiliation: Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada. Electronic address: joshua.lai@alumni.ubc.ca.
authors.forename: Joshua
authors.initials: J
authors.lastname: Lai
authors.affiliation: Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors.forename: Raika
authors.initials: R
authors.lastname: Pancaroglu
authors.affiliation: Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors.forename: Ipek
authors.initials: I
authors.lastname: Oruc
authors.affiliation: Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors.forename: Jason J S
authors.initials: JJ
authors.lastname: Barton
authors.affiliation: Human Vision and Eye Movement Laboratory, Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors.forename: Jodie
authors.initials: J
authors.lastname: Davies-Thompson
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology; D005145:Face; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D009778:Occipital Lobe / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D013647:Task Performance and Analysis; D013702:Temporal Lobe / Q000502:physiology; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
keywords: Eyes; Face recognition; Mouth; Neuroimaging