Impaired face discrimination in acquired prosopagnosia is associated with abnormal response to individual faces in the right middle fusiform gyrus.
The middle fusiform gyrus (MFG) and the inferior occipital gyrus (IOG) are activated by both detection and identification of faces. Paradoxically, patients with acquired prosopagnosia following lesions to either of these regions in the right hemisphere cannot identify faces, but can still detect faces. Here we acquired functional magnetic resonance imaging (fMRI) data during face processing in a patient presenting a specific deficit in individual face recognition, following lesions encompassing the right IOG. Using an adaptation paradigm we show that the fMRI signal in the rMFG of the patient, while being larger in response to faces as compared to objects, does not differ between conditions presenting identical and distinct faces, in contrast to the larger response to distinct faces observed in controls. These results suggest that individual discrimination of faces critically depends on the integrity of both the rMFG and the rIOG, which may interact through re-entrant cortical connections in the normal brain.
Schiltz
Christine
C
Department of Cognitive Development and Laboratory of Neurophysiology, University of Louvain, Belgium. schiltz@nefy.ucl.ac.be
Sorger
Bettina
B
Caldara
Roberto
R
Ahmed
Fatima
F
Mayer
Eugene
E
Goebel
Rainer
R
Rossion
Bruno
B
D004193:Discrimination Learning; D005074:Evoked Potentials, Visual; D005145:Face; D005260:Female; D006801:Humans; D008875:Middle Aged; D009778:Occipital Lobe / Q000503:physiopathology*; D010364:Pattern Recognition, Visual; D020238:Prosopagnosia / Q000503:physiopathology*; D011597:Psychomotor Performance; D013702:Temporal Lobe / Q000503:physiopathology*