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PubMed2006

The time course of visual competition to the presentation of centrally fixated faces.

A recent event-related potential (ERP) study showed that the occipitotemporal component N170 recorded to a face stimulus appearing in the peripheral visual field is strongly reduced when subjects are concurrently fixating another face stimulus. This suggests that concurrently presented face stimuli compete for neural representation in the occipitotemporal cortex between 100 and 200 ms following stimulus onset. We tested whether this competition can be observed for a foveally presented face stimulus appearing next to either two peripheral face pictures or two peripheral control stimuli. The N170 in response to the fixated central face stimulus was substantially reduced (approximately 20% of signal) when it was presented next to peripheral face stimuli. The response suppression was smaller in magnitude than in a previous study where the competing stimulus was fixated and the target stimulus appeared in the periphery. Besides providing a better control for attentional and eye movement confounds, the concurrent stimulation paradigm for fixated face stimuli in ERPs offers a powerful tool to investigate the time course and the nature of the interactions between face and nonface object representations.

Adult↗
PubMed2006

Functional and structural deficits in brain regions subserving face perception in schizophrenia.

OBJECTIVE: Schizophrenia impairs many cognitive functions, including face perception. Veridical face perception is critical for social interaction, including distinguishing friend from foe and familiar from unfamiliar faces. The main aim of this study was to determine whether patients with schizophrenia show less activation in neural networks related to face processing, compared with healthy subjects, and to investigate the relationships between this functional abnormality and anatomical abnormalities in the fusiform gyrus shown with magnetic resonance imaging (MRI). METHOD: Twenty male chronic schizophrenia patients and 16 healthy comparison subjects matched with the patients for age, gender, handedness, and parental socioeconomic status underwent high-spatial-resolution MRI. Event-related potentials elicited by images of faces, cars, and hands were recorded in a separate session. RESULTS: Compared to the healthy subjects, the patients with schizophrenia showed bilateral N170 amplitude reduction in response to images of faces but not to images of other objects. The patients also had smaller bilateral anterior and posterior fusiform gyrus gray matter volumes, compared to the healthy subjects. In addition, right posterior fusiform gyrus volume was significantly correlated with N170 amplitude measured at the right posterior temporal electrode site in response to images of faces in the schizophrenia patients but not in the healthy comparison subjects. CONCLUSIONS: The results provide evidence for deficits in the early stages of face perception in schizophrenia. The association of these deficits with smaller fusiform gyrus volume in patients with schizophrenia, relative to healthy subjects, suggests that the fusiform gyrus is the site of a defective anatomical substrate for face processing in schizophrenia.

Adult↗
PubMed2003

Face imagery and its relation to perception and covert recognition in prosopagnosia.

BACKGROUND: Face imagery can access facial memories without the use of perceptual stimuli. Current data on the relation of imagery to the perceptual function and neuroanatomy of prosopagnosic patients are mixed, and little is known about the type of facial information patients can access through imagery. OBJECTIVE: The authors wished to determine 1) which lesions abolished face imagery in prosopagnosia, 2) if deficits in perceiving facial structure were paralleled by similar deficits in imagery, and 3) if covert recognition of faces correlated with the degree of residual imagery for faces. METHODS: The authors tested nine prosopagnosic patients who had been tested previously for perception of facial configuration and covert recognition of famous faces. The authors constructed a battery of 37 questions that asked subjects to imagine the faces of two celebrities and to choose which one had a certain facial property. Half were questions about facial features and half were about overall facial shape. RESULTS: Imagery was abolished only by anterior temporal lesions. Imagery for facial shape but not features was degraded by lesions of the right hemisphere's fusiform face area, which severely impaired perception of facial configuration. Feature imagery was degraded only when there was associated left occipito-temporal damage. Covert recognition was found when either configural perception or imagery was severely damaged, but not when both were abnormal. In patients with impaired configural perception, covert recognition correlated with feature imagery, suggesting that feature-based processing may drive residual covert abilities in these patients. CONCLUSION: Although anterior temporal cortex may be the site of facial memory stores, these data also support hypotheses that perceptual areas like the fusiform face area have parallel contributions to mental imagery. The data on covert recognition are consistent with a view that it is the residue of a partially damaged face-recognition network. Covert recognition may reflect the degree of damage across components of a network rather than mark a specific form of prosopagnosia or a dissociated pathway.

Age of Onset↗
PubMed2000

Images of a familiar face do not capture attention under conditions of inattention.

Personally and emotionally meaningful information (e.g., one's own name) has shown to capture attention. The question we studied was whether an image of a familiar face draws attention even though it is not expected, and it appears when the focus of attention is directed to other stimuli. Observers' task was to compare two faces and report whether they were identical or left-right reversed. In addition to these faces, a matrix of 'background' faces was displayed. On noncritical trials, the matrix consisted of unfamiliar faces. On critical trials (in about every eighth trial) either an observer's own face or President Ahtisaari's face was displayed. Reaction time was nearly identical on the critical and uncritical trials. On the recognition test about half of the observers were certain that they had seen their own faces in the first part of the experiment. When explicitly asked, however, only three of 26 observers reported that they had recognized their own faces during the comparison task.

Adolescent↗
PubMed2002

Children's face recognition in different contexts: the role of encoding strategies.

In this study, the relationship between face recognition and different facial encoding strategies was investigated. Children (6-8 years, N= 134) participated in both a face recognition task and an encoding task. During the recognition task, they saw 7 target faces in an eyewitness context (video) or in a neutral context (static black and white slides) which they later had to recognize from a set of 21 faces. On the encoding task, the same children had to categorize new faces (schematic and photorealistic) into two categories. The construction of the categories allowed participants to encode the faces either analytically (by focusing on a single attribute) or holistically (in terms of overall similarity). The results showed that face recognition was better in the social than in the neutral context. In the neutral context, only holistic encoding was connected to better face recognition. In the social context, children seemed to use not only information about the faces but also information about the persons.

Affect↗
PubMed2001

Infants attend to second-order relational properties of faces.

Two experiments investigated whether 7-month-old infants attend to the spatial distance measurements relating internal features of the human face. A visual preference paradigm was used, in which two versions of the same female face (one either lengthened or shortened, and one nonmodified) were presented simultaneously. In Experiment 1, infants looked longer at the nonmodified faces, which were determined to match the average distance relationships found in a sample of faces drawn from the same population. Longer looking times for modified faces were found in Experiment 2, in which the nonmodified faces were unusually long and the modified faces conformed to average distance measurements. It is proposed that infants' attention to the spatial relations of internal face features is an optimal tool for lifelong face recognition.

Attention↗
PubMed1991

False recency and false fame of faces in young adulthood and old age.

Studies of age differences in face recognition have shown age-related increases in false-alarm errors: elderly persons exceed young adults in judging new faces to be old. To distinguish among theoretical accounts of this finding, we compared young and elderly subjects in two recognition tasks: (1) that of judging whether faces were recent or nonrecent, and (2) that of judging whether faces were famous or nonfamous. The major independent variable was prior presentation of faces-including nonrecent and nonfamous foils-1 week before the test. False recent judgments in response to nonrecent faces and false famous judgments in response to nonfamous faces were higher among the elderly. Moreover, these age-related differences in false-alarm rates were larger for faces viewed 1 week previously than for entirely new faces. The findings suggest that, compared to young adults, older individuals rely relatively more on perceived familiarity, and relatively less on recollection of context, in making recognition decisions.

Adult↗
PubMed1995

Metamemory, distinctiveness, and event-related potentials in recognition memory for faces.

A neglected topic in metamemory research is the ability of subjects to predict their own recognition performance for faces. We investigated whether subjects can make such judgments of learning (JOL) for unfamiliar faces and whether JOLs relate to facial distinctiveness, a powerful determinant of face recognition. One group of subjects made JOLs, and a second group rated the same faces for distinctiveness; subsequently, both groups tried to recognize these faces among new faces. There was significant prospective metamemory for faces that appeared to be based on facial distinctiveness. Both prospective metamemory and distinctiveness ratings related to long-lasting effects in event-related brain potentials (ERPs), closely resembling an ERP component that predicted face recognition. Therefore, the brain processes underlying JOLs, distinctiveness, and recognition memory for faces appear to be intimately related.

Adult↗
PubMed1991

Familiarity and recognition of faces in old age.

Elderly persons exceed young adults in false recognitions of new faces. One account claims there are age-related deficits in memory for context of encounter with faces. Because of these deficits, elderly persons frequently recognize faces on the basis of perceived familiarity (i.e., resemblance to face representations in memory), which is high for some new faces. To test this context-recollection hypothesis, we had young adult and elderly subjects judge whether faces: (1) had been seen previously in a test (though no face was repeated), and (2) were subjectively familiar (though no face was famous). The elderly exceeded the young subjects in seen-before judgements (false recognitions), and only the elderly showed a positive correlation between false recognitions and subjective familiarity. In Experiment 2, this finding was extended from false recognitions to correct recognitions, supporting the view that elderly persons, compared to young adults, rely more on resemblance in recognizing faces.

Adult↗
PubMed2005

[Effects of configural information on face shape perception].

Several studies have identified the importance of holistic information in face recognition. However, only few studies have investigated how it is influenced by changes of configuration. In Experiment 1, four faces were created by changing the distance between the eyes and the mouth. Participants evaluated the size of the face on three dimensions -- face length, face width and face range by using magnitude estimation. Results indicated that increasing the distance between the eyes and the mouth increased the estimated length and range of faces. In Experiment 2, the distance between the eyes was manipulated in a way similar to Experiment 1. Results indicated that increasing the distance between the eyes increased the estimated width and the range of the face. The direction of face presentation (normal or inverted) only affected width estimation in Experiment 1. It is concluded that facial perception is affected by configural information of features. These results are discussed regarding configural information and inversion effects.

Adult↗
PubMed2002

Gender is a dimension of face recognition.

In an experiment, the authors investigated the impact of gender categorization on face recognition. Participants were familiarized with composite androgynous faces labeled with either a woman's first name (Mary) or a man's first name (John). The results indicated that participants more quickly eliminated faces of the opposite gender than faces of the same gender than the face they were looking for. This gender effect did not result from greater similarity between faces of the same gender. Rather, early gender categorization of a face during face recognition appears to speed up the comparison process between the perceptual input and the facial representation. Implications for face recognition models are discussed.

Adolescent↗
PubMed2002

Activity in the fusiform gyrus predicts conscious perception of Rubin's vase-face illusion.

We localized regions in the fusiform gyrus and superior temporal sulcus that were more active when subjects viewed photographs of real faces than when they viewed complex inanimate objects and other areas in the parahippocampal gyrus and the lateral occipital lobe that showed more activity during the presentation of nonface objects. Event-related functional magnetic resonance imaging was then used to monitor activity in these extrastriate visual areas while subjects viewed Rubin's vase-face stimulus and indicated switches in perception. Since the spontaneous shifts in interpretation were too rapid for direct correlation with hemodynamic responses, each reported percept (faces or vase) was prolonged by suddenly adding subtle local contrast gradients (embossing) to one side or the other of the figure-ground boundary, stabilizing the percept. Under these conditions, only face-selective areas in the fusiform gyrus responded more strongly during the perception of faces. To control for effects of the physical change to Rubin's stimulus (i.e., addition of embossing), we compared activity when the face contours were embossed after the subject had just reported the onset of perception of either faces or vase. Activity in the fusiform face area responded more strongly under the first condition, despite the fact that the physical stimulus sequences were identical. Moreover, on a trial-to-trial basis, the activity was statistically predictive of the subjects' responses, suggesting that the conscious perception of faces could be made explicit in this extrastriate visual area.

Adult↗
PubMed1992

[Discrimination learning of rotated faces: a Markov analysis of coding and association processes].

30 subjects participated in a discrimination experiment learning face-letter associations under four rotation conditions (45 degrees, 90 degrees, 135 degrees, 180 degrees). Under each condition two thirds of the faces were presented twice, upright and rotated away from the vertical; the remaining faces were presented once, upright or rotated. Learning is described by a joint Markov model: For faces that are presented twice it assumes a separate association and encoding process (two-stage-model), for faces that are presented once it assumes an association process (all-or-none-model). The Markov model fits the data for all four rotation conditions. The angle of rotation does not affect learning for faces that are presented once. For faces that are presented twice it influences both the association and the encoding process. For the angles employed, the effect of rotation can be approximated linearly. The results suggest that the encoding of a rotated face differs increasingly from an upright face as a function of these angles of rotation. This confirms analogous conclusions from mental rotation experiments.

Adult↗
PubMed1990

Brain mechanisms for recognition of faces, facial expression, and gestures: neuropsychological and electroencephalographic studies in normals, brain-lesioned patients, and schizophrenics.

The perception and recognition of faces and nonface stimuli were investigated by means of EP techniques in normal subjects. Neuropsychological studies on recognition of faces, facial expression, and gestures were performed in normal subjects, brain-lesioned patients, and schizophrenic patients. 1. Two neuropsychological tests investigating recognition of faces, mimic expression, and gestures were applied in normals and brain-lesioned patients. In the first test, the recognition of faces and vases was tested 1 hr and 1 week after an inspection series. It was found that the size rather than the location of the lesion (excluding occipital lobe lesions) was an important determinant of the error score. No significant differences were found between patients suffering from RH and LH lesions. In general the same observation was true when recognition of faces, expression, and gestures was studied by means of a movie test consisting of 12 10-sec movie scenes and 10 multiple-choice tests following inspection of each scene. A slight tendency to higher error scores appeared in patients suffering from right temporo-occipital lesions compared with other RH lesions. 2. Impairment in the perception and recognition of faces, facial expression, and gestures was also found in schizophrenic patients. Their error score, especially in the movie tests, was on the average higher than in brain-lesioned patients, indicating a major perceptual or cognitive deficit in this disease. This observation is consistent with some clinical symptoms of schizophrenia. It is remarkable that in the slide test, schizophrenic patients had a significantly higher error score in the easy tasks (recognition of upright faces) than normals, whereas in the difficult tasks (involving upside-down faces) their performance was not significantly different from that of an age- and socially matched group. 3. The degree of schizophrenic defect and acute psychotic symptoms had some effect on the impairment in schizophrenics performing these tests. When the error scores of adolescent and middle-aged schizophrenics were compared to corresponding control group error scores, the relative impairment of adolescent schizophrenic patients was found to be somewhat stronger than that of adult schizophrenics. This supports the hypothesis that the impairment in face and mimic recognition found in schizophrenic patients is caused by the disease and not by other factors such as duration of illness or hospitalization. It is conjectured that a component very specific to schizophrenia leads to the dramatic cognitive defect found in our tests in these patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain Diseases↗
PubMed1984

Neurons in the cortex of the temporal lobe and in the amygdala of the monkey with responses selective for faces.

There are populations of neurons in the temporal lobe of the macaque which appear to be specialised to respond to faces. These neurons are relatively rare in the inferior temporal visual cortex, area TE, but are more common in the cortex in the middle and anterior parts of the superior temporal sulcus. In some cases these neurons can respond to parts of faces such as the eyes, and in other cases a fuller complement of the features present in faces, with even the correct configuration of these features, appears to be necessary for these neurons to respond. In experiments to investigate whether the responses of these neurons would be useful for recognition of an individual, it has been shown that in many cases (77% of one sample), these neurons are sensitive to differences between faces. In experiments designed to investigate the information required for these neurons to respond, it has been shown that these neurons can respond to blurred images of faces, and to faces with only the high spatial frequencies included. A population of neurons with face-selective responses has also been found in the amygdala, which receives inputs from the temporal lobe visual cortex. In many cases these neurons respond differently to different faces. It is suggested that the importance of this type of neuron may be in the different emotional and social responses which occur to different faces, and which are disrupted by damage to the amygdala.

Amygdala↗
PubMed2005

Enhanced extrastriate visual response to bandpass spatial frequency filtered fearful faces: time course and topographic evoked-potentials mapping.

We compared electrical brain responses to fearful vs. neutral facial expressions in healthy volunteers while they performed an orthogonal gender decision task. Face stimuli either had a broadband spatial-frequency content, or were filtered to create either low spatial-frequency (LSF) or high spatial-frequency (HSF) faces, always overlapped with their complementary SF content in upside-down orientation to preserve the total stimulus energy. We tested the hypothesis that the coarse LSF content of faces might be responsible for an early modulation of event-related potentials (ERPs) to fearful expressions. Consistent with previous findings, we show that broadband images of fearful faces, relative to neutral faces, elicit a higher global field power of approximately 130 ms poststimulus onset, corresponding to an increased P1 component over lateral occipital electrodes, with neural sources located within the extrastriate visual cortex. Bandpass filtering of faces strongly affected the latency and amplitude of ERPs, with a suppression of the normal N170 response for both LSF and HSF faces, irrespective of expression. Critically, we found that LSF information from fearful faces, unlike HSF information, produced a right-lateralized enhancement of the lateral occipital P1, without any change in the scalp topography, relative to unfiltered (broadband) fearful faces. These results demonstrate that an early P1 response to fear expression depends on a visual pathway preferentially tuned to coarse-magnocellular inputs, and can persist unchanged even when the N170 generators are disrupted by SF filtering.

Adult↗
PubMed2004

Discrimination of face identities and expressions in children with autism: same or different?

Autism is a pervasive developmental disorder (PDD) characterized by the association of communication and socialization impairments, and by repetitive stereotyped behaviours. The Minnesota Test of Affective Processing (MNTAP) was used to investigate the discrimination of face identities and face expressions by autistic children. Young children in the 6- to 10-year-old age range suffering from PDD were compared to paired normal children. When the expressions on faces remained neutral, autistic patients had more difficulty in distinguishing different faces than in matching the same facial identities in face pairs: they perceived different faces as being identical. However, recognition errors disappeared when expressions were changed together with face identity. When autistic children were asked to distinguish expressions, they discriminated better identity than difference, just as normal children do. Analysis of face and expression discrimination in terms of identity and difference is a novel approach for the understanding of the clinical features of autism. Autistic children seek sameness and use an atypical strategy to analyse human faces and expressions.

Autistic Disorder↗
PubMed2006

Event-related brain potential correlates of emotional face processing.

Results from recent event-related brain potential (ERP) studies investigating brain processes involved in the detection and analysis of emotional facial expression are reviewed. In all experiments, emotional faces were found to trigger an increased ERP positivity relative to neutral faces. The onset of this emotional expression effect was remarkably early, ranging from 120 to 180ms post-stimulus in different experiments where faces were either presented at fixation or laterally, and with or without non-face distractor stimuli. While broadly distributed positive deflections beyond 250ms post-stimulus have been found in previous studies for non-face stimuli, the early frontocentrally distributed phase of this emotional positivity is most likely face-specific. Similar emotional expression effects were found for six basic emotions, suggesting that these effects are not primarily generated within neural structures specialised for the automatic detection of specific emotions. Expression effects were eliminated when attention was directed away from the location of peripherally presented emotional faces, indicating that they are not linked to pre-attentive emotional processing. When foveal faces were unattended, expression effects were attenuated, but not completely eliminated. It is suggested that these ERP correlates of emotional face processing reflect activity within a neocortical system where representations of emotional content are generated in a task-dependent fashion for the adaptive intentional control of behaviour. Given the early onset of the emotion-specific effects reviewed here, it is likely that this system is activated in parallel with the ongoing evaluation of emotional content in the amygdala and related subcortical brain circuits.

Brain↗