Fusiform face area
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The Fusiform face area (FFA) is a part of the human visual system which seems to specialize in facial recognition.
The FFA is located in the ventral stream on the ventral surface of the temporal lobe on the fusiform gyrus. It is adjacent to the parahippocampal place area and near the putative extrastriate body area. The human FFA was first described by Justine Sergent (deceased) in 1992 (Sergent, Ohta, & MacDonald, Brain 1992, 115:15-36.) and more recently by Nancy Kanwisher (currently at MIT) in 1997 (Kanwisher, McDermott & Chun, J Neurosci 1997, 17(11):4302-1), who proposed and maintains that the existence of the FFA is evidence for domain specificity in the visual system. It is in a slightly different place for each human and displays some lateralization, usually being larger in the right hemisphere.
The FFA was discovered and continues to be investigated in humans using PET and fMRI. Usually, a participant views images of faces, objects, places, bodies, scrambled faces, scrambled objects, scrambled places and scrambled bodies. This is called a functional localizer. Comparing the neural response between faces and scrambled faces will reveal areas that are face-responsive, while comparing cortical activation between faces and objects will reveal areas that are face-selective.
Some groups, including Isabel Gauthier and others maintain that the FFA is an area for recognizing fine distinctions between well-known objects. Gauthier and others have tested both car and bird experts, and found some activation in FFA when car experts were identifying cars and when bird experts were identifying birds (Gauthier et al Nature Neuroscience 2000, 3(2); 191-7, but see McKone et al., 2007, Trends in Cognitive Science).
Highly relevant to our understanding of this pea-sized area of the brain is a recent paper by Kalanit Grill-Spector (Grill-Spector, Sayres, & Ress, Nature Neuroscience 2006, 9; 1177-1185). Critically, there was a Corrigendum which appeared in Nature Neuroscience 2007, 10, 133 along with two commentaries (and what seemed to be a rather aggressive editorial in which the editors blamed the reviewers for any errors). Clearly there were errors in the original paper, yet even in this context, it seems that the field needs to rethink its interpretations of FFA. In particular, there seems little doubt that previous studies arguing for a face-selective "module" were observing data that was the result of averaging over face-selective and non-face-selective subregions. That is, FFA as previously construed is heterogeneous.