Fusiform face area
Encyclopedia
The fusiform face area is a part of the human visual system
which might be specialized for facial recognition
, although there is some evidence that it also processes categorical information about other objects, particularly familiar ones.
on the fusiform gyrus
. It is adjacent to the parahippocampal place area and near the putative extrastriate body area. 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 positron emission tomography
(PET) and functional magnetic resonance imaging
(fMRI) studies. 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.
in 1997 who proposed that the existence of the FFA is evidence for domain specificity
in the visual system. More recently, it has been suggested that the FFA processes more than just faces. Some groups, including Isabel Gauthier
and others, maintain that the FFA is an area for recognizing fine distinctions between well-known objects. Gauthier et al. tested both car and bird experts, and found some activation in the FFA when car experts were identifying cars and when bird experts were identifying birds. A recent paper by Kalanit Grill-Spector et al. also suggests that processing in the FFA is not exclusive to faces, although an erratum
was later published which brought to light some errors. The debate about the functional role of the FFA is ongoing.
A 2009 magnetoencephalography
study found that objects incidentally perceived as faces, an example of pareidolia
, evoke an early (165 ms) activation in the FFA, at a time and location similar to that evoked by faces, whereas other common objects do not evoke such activation. This activation is similar to a slightly earlier peak at 130 ms seen for images of real faces. The authors suggest that face perception evoked by face-like objects is a relatively early process, and not a late cognitive reinterpretation phenomenon.
One case study
on prosopagnosia
provided evidence that faces are processed in a special way. A patient known as C. K., who suffered brain damage
as a result of a car accident, later developed object agnosia
. He experienced great difficulty with basic level object recognition, also extending to body parts, but performed very well at recognizing faces. A later study showed that C. K. was unable to recognize faces that were inverted or otherwise distorted, even in cases where they could easily be identified by normal subjects. This is taken as evidence that the fusiform face area is specialized for processing faces in a normal orientation.
Visual system
The visual system is the part of the central nervous system which enables organisms to process visual detail, as well as enabling several non-image forming photoresponse functions. It interprets information from visible light to build a representation of the surrounding world...
which might be specialized for facial recognition
Face perception
Face perception is the process by which the brain and mind understand and interpret the face, particularly the human face.The human face's proportions and expressions are important to identify origin, emotional tendencies, health qualities, and some social information. From birth, faces are...
, although there is some evidence that it also processes categorical information about other objects, particularly familiar ones.
Localization
The FFA is located in the ventral stream on the ventral surface of the temporal lobeTemporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
on the fusiform gyrus
Fusiform gyrus
The fusiform gyrus is part of the temporal lobe in Brodmann Area 37. It is also known as the occipitotemporal gyrus. Other sources have the fusiform gyrus above the occipitotemporal gyrus and underneath the parahippocampal gyrus....
. It is adjacent to the parahippocampal place area and near the putative extrastriate body area. It is in a slightly different place for each human and displays some lateralization, usually being larger in the right hemisphere
Cerebral hemisphere
A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...
.
The FFA was discovered and continues to be investigated in humans using positron emission tomography
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
(PET) and functional magnetic resonance imaging
Functional magnetic resonance imaging
Functional magnetic resonance imaging or functional MRI is a type of specialized MRI scan used to measure the hemodynamic response related to neural activity in the brain or spinal cord of humans or other animals. It is one of the most recently developed forms of neuroimaging...
(fMRI) studies. 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.
Functional role
The human FFA was first described by Justine Sergent in 1992 and by Nancy KanwisherNancy Kanwisher
Nancy Kanwisher is a Professor in the McGovern Institute for Brain Research at MIT. She studies the neural and cognitive mechanisms underlying human visual perception and cognition. Her work investigates object recognition, visual attention, and perceptual awareness, as well as response selection,...
in 1997 who proposed that the existence of the FFA is evidence for domain specificity
Domain specificity
Domain specificity is a theoretical position in cognitive science that argues that many aspects of cognition are supported by specialized, presumably evolutionarily specified, learning devices...
in the visual system. More recently, it has been suggested that the FFA processes more than just faces. Some groups, including Isabel Gauthier
Isabel Gauthier
Isabel Gauthier is a cognitive neuroscientist currently holding the position of professor and head of the Object Perception Lab at Vanderbilt University’s Department of Psychology, where she is also the co-director of the Cognition and Cognitive Neuroscience graduate program. She was born in...
and others, maintain that the FFA is an area for recognizing fine distinctions between well-known objects. Gauthier et al. tested both car and bird experts, and found some activation in the FFA when car experts were identifying cars and when bird experts were identifying birds. A recent paper by Kalanit Grill-Spector et al. also suggests that processing in the FFA is not exclusive to faces, although an erratum
Erratum
An erratum or corrigendum is a correction of a book. An erratum is most commonly issued shortly after its original text is published. Patches to security issues in a computer program are also sometimes called errata. As a general rule, publishers issue an erratum for a production error An erratum...
was later published which brought to light some errors. The debate about the functional role of the FFA is ongoing.
A 2009 magnetoencephalography
Magnetoencephalography
Magnetoencephalography is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using arrays of SQUIDs...
study found that objects incidentally perceived as faces, an example of pareidolia
Pareidolia
Pareidolia is a psychological phenomenon involving a vague and random stimulus being perceived as significant. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records played in reverse...
, evoke an early (165 ms) activation in the FFA, at a time and location similar to that evoked by faces, whereas other common objects do not evoke such activation. This activation is similar to a slightly earlier peak at 130 ms seen for images of real faces. The authors suggest that face perception evoked by face-like objects is a relatively early process, and not a late cognitive reinterpretation phenomenon.
One case study
Case study
A case study is an intensive analysis of an individual unit stressing developmental factors in relation to context. The case study is common in social sciences and life sciences. Case studies may be descriptive or explanatory. The latter type is used to explore causation in order to find...
on prosopagnosia
Prosopagnosia
Prosopagnosia is a disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intact...
provided evidence that faces are processed in a special way. A patient known as C. K., who suffered brain damage
Brain damage
"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
as a result of a car accident, later developed object agnosia
Agnosia
Agnosia is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss...
. He experienced great difficulty with basic level object recognition, also extending to body parts, but performed very well at recognizing faces. A later study showed that C. K. was unable to recognize faces that were inverted or otherwise distorted, even in cases where they could easily be identified by normal subjects. This is taken as evidence that the fusiform face area is specialized for processing faces in a normal orientation.
Further reading
- McKone et al., Trends in Cognitive Science, 2007
- Carlson, Neil R., Physiology of Behavior, 9th ed., 2007. ISBN 0-205-46724-5
- Bukach, C. M., I. Gauthier, and M. Tarr. 2006. Beyond faces and modularity: The power of an expertise framework. TRENDS in Cognitive Sciences 10:159-166.