Dissociation between overt and unconscious face processing in fusiform face area (original) (raw)
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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).
Neural substrates for the recognition of newly learned faces: a functional MRI study
Neuropsychologia, 2000
Face recognition is critical to the appreciation of our social and physical relations. Functional magnetic resonance imaging (fMRI) was used to identify brain regions involved in the recognition of newly learned faces. Two experiments were conducted. Experiment 1 contrasted a fixation control task with a face recognition task in which subjects were exposed solely to previously viewed faces (all-target). Experiment 2 compared a fixation control with another face recognition task in which subjects were presented with both novel and viewed faces (half-target). Compared to the fixation control, the all-target face recognition was associated with activation in the bilateral occipital and occipitotemporal regions, whereas the half-target face recognition produced activation in the right parietal and prefrontal regions, in addition to the occipital and occipitotemporal. The all-target minus half-target comparison revealed significant activation in the bilateral fusiform gyrus, suggesting stronger fusiform activity during the all-target than the half-target face recognition. The half-target minus all-target comparison showed significant activation in the superior and inferior parietal lobules and several regions in the right frontal lobe. These findings demonstrated that the bilateral fusiform gyrus is involved, not only in face perception, but in a certain aspect of face recognition memory and that this aspect is related to the actual recognition of previously viewed faces rather than the processing of novel ones, which results are consistent with previous lesion work. The right parietal and frontal regions, in contrast, are differentially more associated with the processes related to the detection of novel faces or retrieval effort.
The neuropsychology of face perception: beyond simple dissociations and functional selectivity
Philosophical Transactions of the Royal Society B: Biological Sciences, 2011
Face processing relies on a distributed, patchy network of cortical regions in the temporal and frontal lobes that respond disproportionately to face stimuli, other cortical regions that are not even primarily visual (such as somatosensory cortex), and subcortical structures such as the amygdala. Higher-level face perception abilities, such as judging identity, emotion and trustworthiness, appear to rely on an intact face-processing network that includes the occipital face area (OFA), whereas lower-level face categorization abilities, such as discriminating faces from objects, can be achieved without OFA, perhaps via the direct connections to the fusiform face area (FFA) from several extrastriate cortical areas. Some lesion, transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) findings argue against a strict feed-forward hierarchical model of face perception, in which the OFA is the principal and common source of input for other visual and non-vis...
Face encoding and recognition in the human brain
Proceedings of the National Academy of Sciences, 1996
A dissociation between human neural systems that participate in the encoding and later recognition of new memories for faces was demonstrated by measuring memory task-related changes in regional cerebral blood flow with positron emission tomography. There was almost no overlap between the brain structures associated with these memory functions. A region in the right hippocampus and adjacent cortex was activated during memory encoding but not during recognition. The most striking finding in neocortex was the lateralization of prefrontal participation. Encoding activated left prefrontal cortex, whereas recognition activated right prefrontal cortex. These results indicate that the hippocampus and adjacent cortex participate in memory function primarily at the time of new memory encoding. Moreover, face recognition is not mediated simply by recapitulation of operations performed at the time of encoding but, rather, involves anatomically dissociable operations.
Neuroreport, 2008
We explored the processing mechanisms of featural and con¢gural face information using event-related functional magnetic resonance imaging. Featural information describes the information contained in the facial parts; con¢gural information conveys the spatial interrelationship between parts. In a delayed matching-to-sample task, participants decided whether an intact test face matched a precedent scrambled or blurred cue face. Scrambled faces primarily contain featural information whereas blurred faces preserve con¢gural information. Scrambled cue faces evoked enhanced activation in the left fusiform gyrus, left parietal lobe, and left lingual gyrus when viewing intact test faces. Following blurred cue faces, test faces enhanced activation bilaterally in the middle temporal gyrus. The results suggest that featural and con¢gural information is processed by following distinct neural pathways. NeuroReport 19:287^291
Journal of Cognitive Neuroscience, 2012
■ In this study, we explored the neural correlates of perceptual awareness during a masked face detection task. To assess awareness more precisely than in previous studies, participants employed a 4-point scale to rate subjective visibility. An eventrelated fMRI and a high-density ERP study were carried out. Imaging data showed that conscious face detection was linked to activation of fusiform and occipital face areas. Frontal and parietal regions, including the pre-SMA, inferior frontal sulcus, anterior insula/frontal operculum, and intraparietal sulcus, also responded strongly when faces were consciously perceived. In contrast, no brain area showed face-selective activity when participants reported no impression of a face. ERP results showed that conscious face detection was associated with enhanced N170 and also with the presence of a second negativity around 300 msec and a slow positivity around 415 msec. Again, face-related activity was absent when faces were not consciously perceived. We suggest that, under conditions of backward masking, ventral stream and fronto-parietal regions show similar, strong links of face-related activity to conscious perception and stress the importance of a detailed assessment of awareness to examine activity related to unseen stimulus events. ■
Cognitive Response Profile of the Human Fusiform Face Area as Determined by MEG
Cerebral Cortex, 2000
Activation in or near the fusiform gyrus was estimated to faces and control stimuli. Activation peaked at 165 ms and was strongest to digitized photographs of human faces, regardless of whether they were presented in color or grayscale, suggesting that face-and color-specific areas are functionally separate. Schematic sketches evoked ∼30% less activation than did face photographs. Scrambling the locations of facial features reduced the response by ∼25% in either hemisphere, suggesting that configurational versus analytic processing is not lateralized at this latency. Animal faces evoked ∼50% less activity, and common objects, animal bodies or sensory controls evoked ∼80% less activity than human faces. The (small) responses evoked by meaningless control images were stronger when they included surfaces and shading, suggesting that the fusiform gyrus may use these features in constructing its facespecific response. Putative fusiform activation was not significantly related to stimulus repetition, gender or emotional expression. A midline occipital source significantly distinguished between faces and control images as early as 110 ms, but was more sensitive to sensory qualities. This source significantly distinguished happy and sad faces from those with neutral expressions. We conclude that the fusiform gyrus may selectively encode faces at 165 ms, transforming sensory input for further processing.
European Journal of Neuroscience, 2010
Neuroimaging studies of humans have provided inconsistent evidence with respect to the response properties of the fusiform face area (FFA). It has been claimed that neural populations within this region are sensitive to subtle differences between individual faces only when they are perceived as distinct identities [P. Rotshtein et al. (2005) Nature Neuroscience, 8, 107-113]. However, sensitivity to subtle changes of identity was found in previous studies using unfamiliar faces, for which categorical perception is less pronounced. Using functional magnetic resonance adaptation and morph continua of personally familiar faces, we investigated sensitivity to subtle changes between faces that were located either on the same or opposite sides of a categorical perceptual boundary. We found no evidence for categorical perception within the FFA, which exhibited reliable sensitivity to subtle changes of face identity whether these were perceived as distinct identities, or not. On the contrary, both the posterior superior temporal sulcus and prefrontal cortex exhibited categorical perception, as subtle changes between faces perceived as different identities yielded larger release from adaptation than those perceived as the same identity. These observations suggest that, whereas the FFA discriminates subtle physical changes of personally familiar faces, other regions encode faces in a categorical fashion.
Anatomical connections underlying personally-familiar face processing
PLOS ONE, 2019
Familiar face processing involves face specific regions (the core face system) as well as other non-specific areas related to processing of person-related information (the extended face system). The connections between core and extended face system areas must be critical for face recognition. Some studies have explored the connectivity pattern of unfamiliar face responding area, but none have explored those areas related to face familiarity processing in the extended system. To study these connections, diffusion weighted imaging with probabilistic tractography was used to estimate the white-matter pathways between core and extended system regions, which were defined from functional magnetic resonance imaging responses to personally-familiar faces. Strong white matter connections were found between occipitotemporal face areas (OFA/FFA) with superior temporal sulcus and insula suggesting the possible existence of direct anatomical connections from face-specific areas to frontal nodes that could underlay the processing of emotional information associated to familiar faces.
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.