Abnormal face identity coding in the middle fusiform gyrus of two brain-damaged prosopagnosic patients.
We report a functional magnetic resonance imaging (fMRI) adaptation study of two well-described patients, DF and PS, who present face identity recognition impairments (prosopagnosia) following brain-damage. Comparing faces to non-face objects elicited activation in all visual areas of the cortical face processing network that were spared subsequent to brain damage. The common brain lesion in the two patients was in the right inferior occipital cortex, in the territory of the right "occipital face area" ('OFA'), which strengthens the critical role of this region in processing faces. Despite the lesion to the right 'OFA', there was normal range of sensitivity to faces in the right "fusiform face area" ('FFA') in both patients, supporting a non-hierarchical model of face processing at the cortical level. At the same time, however, sensitivity to individual face representations, as indicated by release from adaptation to identity, was abnormal in the right 'FFA' of both patients. This suggests that the right 'OFA' is necessary to individualize faces, perhaps through reentrant interactions with other cortical face sensitive areas. The lateral occipital area (LO) is damaged bilaterally in patient DF, who also shows visual object agnosia. However, in patient PS, in whom LO was spared, sensitivity to individual representations of non-face objects was still found in this region, as in the normal brain, consistent with her preserved object recognition abilities. Taken together, these observations, which fruitfully combine functional imaging and neuropsychology, place strong constraints on the possible functional organization of the cortical areas mediating face processing in the human brain.
Steeves
Jennifer
J
Centre for Vision Research, Department of Psychology, York University, Toronto, Canada. steeves@yorku.ca
Dricot
Laurence
L
Goltz
Herbert C
HC
Sorger
Bettina
B
Peters
Judith
J
Milner
A David
AD
Goodale
Melvyn A
MA
Goebel
Rainer
R
Rossion
Bruno
B
D001930:Brain Injuries / Q000150:complications; D001931:Brain Mapping; D005145:Face / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000098:blood supply / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009778:Occipital Lobe / Q000098:blood supply / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D020238:Prosopagnosia / Q000209:etiology / Q000473:pathology*; D021641:Recognition, Psychology / Q000502:physiology*
D010100:Oxygen