The neuropsychology of face perception: beyond simple dissociations and functional selectivity (original) (raw)
Related papers
2010
Controversy surrounds the proposal that specific human cortical regions in the ventral occipitotemporal cortex, commonly called the fusiform face area (FFA) and occipital face area (OFA), are specialized for face processing. Here, we present findings from an fMRI study of identity discrimination of faces and objects that demonstrates the FFA and OFA are equally responsive to processing stimuli at the level of individuals (i.e., individuation), be they human faces or non-face objects. The FFA and OFA were defined via a passive viewing task as regions that produced greater activation to faces relative to non-face stimuli within the middle fusiform gyrus and inferior occipital gyrus. In the individuation task, participants judged whether sequentially presented images of faces, diverse objects, or wristwatches depicted the identical or a different exemplar. All three stimulus types produced equivalent BOLD activation within the FFA and OFA; that is, there was no face-specific or face-preferential processing. Critically, individuation processing did not eliminate an object superiority effect relative to faces within a region more closely linked to object processing in the lateral occipital complex (LOC), suggesting that individuation processes are reasonably specific to the FFA and OFA. Taken together, these findings challenge the prevailing view that the FFA and OFA are face-specific processing regions, demonstrating instead that they function to individuate -i.e., identify specific individuals -within a category. These findings have significant implications for understanding the function of brain regions widely believed to play an important role in social cognition.
TMS to the ‘‘occipital face area’’ affects recognition but not categorization of faces
The human cortical system for face perception is comprised of a network of connected regions including the middle fusiform gyrus (''fusiform face area'' or FFA), the inferior occipital cortex (''occipital face area'' or OFA), and the superior temporal sulcus. The traditional hierarchical feedforward model of visual processing suggests information flows from early visual cortex to the OFA for initial face feature analysis to higher order regions including the FFA for identity recognition. However, patient data suggest an alternative model. Patients with acquired prosopagnosia, an inability to visually recognize faces, have been documented with lesions to the OFA but who nevertheless show face-selective activation in the FFA. Moreover, their ability to categorize faces remains intact. This suggests that the FFA is not solely responsible for face recognition and the network is not strictly hierarchical, but may be organized in a reverse hierarchical fashion. We used transcranial magnetic stimulation (TMS) to temporarily disrupt processing in the OFA in neurologically-intact individuals and found participants' ability to categorize intact versus scrambled faces was unaffected, however face identity discrimination was significantly impaired. This suggests that face categorization but not recognition can occur without the ''earlier'' OFA being online and indicates that ''lower level'' face category processing may be assumed by other intact face network regions such as the FFA. These results are consistent with the patient data and support a non-hierarchical, global-to-local model with re-entrant connections between the OFA and other face processing areas.
The Lateral Occipital Cortex in the Face Perception Network: An Effective Connectivity Study
Frontiers in Psychology, 2012
The perception of faces involves a large network of cortical areas of the human brain. While several studies tested this network recently, its relationship to the lateral occipital (LO) cortex known to be involved in visual object perception remains largely unknown. We used functional magnetic resonance imaging and dynamic causal modeling (DCM) to test the effective connectivity among the major areas of the face-processing core network and LO. Specifically, we tested how LO is connected to the fusiform face area (FFA) and occipital face area (OFA) and which area provides the major face/object input to the network. We found that LO is connected via significant bidirectional connections to both OFA and FFA, suggesting the existence of a triangular network. In addition, our results also suggest that face-and object-related stimulus inputs are not entirely segregated at these lower level stages of face-processing and enter the network via the LO. These results support the role of LO in face perception, at least at the level of face/non-face stimulus discrimination.
Perception of Face Parts and Face Configurations: An fMRI Study
Journal of Cognitive Neuroscience, 2010
■ fMRI studies have reported three regions in human ventral visual cortex that respond selectively to faces: the occipital face area (OFA), the fusiform face area (FFA), and a face-selective region in the superior temporal sulcus (fSTS). Here, we asked whether these areas respond to two first-order aspects of the face argued to be important for face perception, face parts (eyes, nose, and mouth), and the T-shaped spatial configuration of these parts. Specifically, we measured the magnitude of response in these areas to stimuli that (i) either contained real face parts, or did not, and (ii) either had veridical face configura-tions, or did not. The OFA and the fSTS were sensitive only to the presence of real face parts, not to the correct configuration of those parts, whereas the FFA was sensitive to both face parts and face configuration. Further, only in the FFA was the response to configuration and part information correlated across voxels, suggesting that the FFA contains a unified representation that includes both kinds of information. In combination with prior results from fMRI, TMS, MEG, and patient studies, our data illuminate the functional division of labor in the OFA, FFA, and fSTS. ■
The fusiform face area subserves face perception, not generic within-category identification
Nature Neuroscience, 2004
The function of the fusiform face area (FFA), a face-selective region in human extrastriate cortex, is a matter of active debate. Here we measured the correlation between FFA activity measured by functional magnetic resonance imaging (fMRI) and behavioral outcomes in perceptual tasks to determine the role of the FFA in the detection and within-category identification of faces and objects. Our data show that FFA activation is correlated on a trial-by-trial basis with both detecting the presence of faces and identifying specific faces. However, for most non-face objects (including cars seen by car experts), within-category identification performance was correlated with activation in other regions of the ventral occipitotemporal cortex, not the FFA. These results indicate that the FFA is involved in both detection and identification of faces, but that it has little involvement in within-category identification of non-face objects (including objects of expertise).
Face-specific responses from the human inferior occipito-temporal cortex
Neuroscience, 1997
Whole-head neuromagnetic responses were recorded from seven subjects to pictures of faces and to various control stimuli. Four subjects displayed signals specific to faces. The combination of functional information from magnetoencephalography and anatomical data from magnetic resonance images suggests that the face-specific activity was generated in the inferior occipitotemporal cortex. All four subjects showed the face-specific response in the right hemisphere, one of them also in the left.
Brain and Cognition, 2012
A number of human brain areas showing a larger response to faces than to objects from different categories, or to scrambled faces, have been identified in neuroimaging studies. Depending on the statistical criteria used, the set of areas can be overextended or minimized, both at the local (size of areas) and global (number of areas) levels. Here we analyzed a whole-brain factorial functional localizer obtained in a large sample of right-handed participants (40). Faces (F), objects (O; cars) and their phase-scrambled counterparts (SF, SO) were presented in a block design during a one-back task that was well matched for difficulty across conditions. A conjunction contrast at the group level {(F-SF) and (F-O)} identified six clusters: in the pulvinar, inferior occipital gyrus (so-called OFA), middle fusiform gyrus (so-called FFA), posterior superior temporal sulcus, amygdala, and anterior infero-temporal cortex, which were all strongly right lateralized. While the FFA showed the largest difference between faces and cars, it also showed the least face-selective response, responding more to cars than scrambled cars. Moreover, the FFA's larger response to scrambled faces than scrambled cars suggests that its face-sensitivity is partly due to low-level visual cues. In contrast, the pattern of activation in the OFA points to a higher degree of face-selectivity. A BOLD latency mapping analysis suggests that face-sensitivity emerges first in the right FFA, as compared to all other areas. Individual brain analyses support these observations, but also highlight the large amount of interindividual variability in terms of number, height, extent and localization of the areas responding preferentially to faces in the human ventral occipito-temporal cortex. This observation emphasizes the need to rely on different statistical thresholds across the whole brain and across individuals to define these areas, but also raises some concerns regarding any objective labeling of these areas to make them correspond across individual brains. This large-scale analysis helps understanding the set of face-sensitive areas in the human brain, and encourages in-depth single participant analyses in which the whole set of areas is considered in each individual brain.
The neural code behind face recognition abilities
bioRxiv (Cold Spring Harbor Laboratory), 2022
Why are some individuals better at recognising faces? We addressed this question by characterising the brain computations of individuals with extraordinary recognition abilities using high-density electroencephalographic signals and a combination of behavioural tests, artificial neural network models, and machine learning analyses. We found that individual face recognition ability can be decoded from brain activity in an extended temporal interval for face and non-face objects. We show that both visual and semantic brain computations contribute to these individual differences. Main The ability to robustly recognise the faces of our colleagues, friends and family members is paramount to our success as social beings. Our brains complete this feat with apparent ease and speed, in a series of computations unfolding within tens of milliseconds in a wide brain network comprising the inferior occipital gyrus, the fusiform gyrus, the superior temporal sulcus, and more anterior areas such as the anterior temporal lobe (Duchaine & Yovel, 2015; Grill-Spector et al., 2017; Kanwisher et al., 1997). Not all individuals, however, are equally competent at recognising faces in their surroundings (White & Burton, 2022). Developmental prosopagnosics show a great difficulty at this task despite an absence of brain injury (Susilo & Duchaine, 2013). In contrast, super-recognisers exhibit remarkable abilities for processing facial identity, who can recognize individuals even after little exposure several years before (Noyes et al., 2017; Ramon, 2021; Russell et al., 2009). The specific nature of the neural processes responsible for these individual differences remains largely unknown. So far, individual differences studies have used univariate techniques to investigate face-specific aspects of brain processing. This revealed that the contrast between responses to faces compared to non-faces, measured by the N170 event-related potential component or by the blood oxygen level dependent signals in regions of interest, are modulated by ability (Elbich &
Beyond the FFA: Brain-behavior correspondences in face recognition abilities
NeuroImage, 2017
Despite the thousands of papers investigating the neural basis of face perception in both humans and nonhuman primates, very little is known about how activation within this neural architecture relates to face processing behavior. Here, we investigated individual differences in brain-behavior correspondences within both core and extended regions of the face-processing system in healthy typically developing adults. To do so, we employed a set of behavioral and neural measures to capture a multifaceted perspective on assessing these brain-behavior relations. This included quantifying face and object recognition behavior, the magnitude and size of functional activation within each region, as well as a measure of global activation across regions. We report that face, but not object, recognition behavior was associated with 1) the magnitude of face-selective activation in the left FFA1, 2) larger face-related regions in multiple bilateral face-patches in the fusiform gyri as well as the bilateral anterior temporal lobe and amygdala, and 3) more distributed global face-network activation. In contrast, face recognition behavior was not associated with any measure of objector place-selective activation. These findings suggest that superior behavior is served by engaging sufficiently large, distributed patches of neural real estate, which might reflect the integration of independent populations of neurons that enables the formation of richer representations.