False recognition of faces associated with fronto-temporal dementia with prosopagnosia

INTRODUCTION: The association of prosopagnosia and false recognition of faces is unusual and contributes to our understanding of the generation of facial familiarity. METHOD: A 67-year-old man with a left prefrontal traumatic lesion, developed a temporal variety of fronto-temporal dementia (semantic dementia) with amyotrophic lateral sclerosis. Cerebral imagery demonstrated a bilateral, temporal anterior atrophy predominating in the right hemisphere. The main cognitive signs consisted in severe difficulties to recognize faces of familiar people (prosopagnosia), associated with systematic false recognition of unfamiliar people. RESULT: Neuropsychological testing indicated that the prosopagnosia probably resulted from the association of an associative/mnemonic mechanism (inability to activate the Face Recognition Units (FRU) from the visual input) and a semantic mechanism (degradation of semantic/biographical information or deconnexion between FRU and this information). At the early stage of the disease, the patient could activate residual semantic information about individuals from their names, but after a 4-year course, he failed to do so. This worsening could be attributed to the extension of the degenerative lesions to the left temporal lobe. Familiar and unfamiliar faces triggered a marked feeling of knowing. False recognition concerned all the unfamiliar faces, and the patient claimed spontaneously that they corresponded to actors, but he could not provide any additional information about their specific identities. The coexistence of prosopagnosia and false recognition suggests the existence of different interconnected systems processing face recognition, one intended to identification of individuals, and the other producing the sense of familiarity. Dysfunctions at different stages of one or the other of these two processes could result in distortions in the feeling of knowing. CONCLUSION: From this case and others reported in literature, we propose to complete the classical model of face processing by adding a pathway linked to limbic system and frontal structures. This later pathway could normally emit signals for familiarity, essentially autonomic, in response to the familiar faces. These signals, primitively unconscious, secondly reach consciousness and are then integrated by a central supervisor system which evaluates and verifies identity-specific biographical information in order to make a decision about the sense of familiarity.     

Oxytocin increases recognition of masked emotional faces

The neuropeptide oxytocin has been shown to improve many aspects of social cognitive functioning, including facial emotion recognition, and to promote social approach behaviour. In the present study, we investigated the modulatory effects of oxytocin on the recognition of briefly presented facial expressions. In order to diversify the degree of visual awareness for the facial stimuli, presentation duration was systematically varied. Fifty-six participants were administered intranasal oxytocin or a placebo in a double-blind, randomized, between-subjects design. Participants viewed angry and happy target faces or neutral distractors for 18, 35, or 53 ms subsequently masked by neutral faces. Participants had to indicate the presence or absence of the briefly presented target face. Discrimination indices (d') showed that oxytocin generally enhanced detection accuracy of emotional stimuli. This effect was more pronounced for the recognition of happy faces. We provide evidence that a single dose of intranasally administered oxytocin enhances detection of briefly presented emotional stimuli. The possible role of stimulus valence and recognition difficulty is discussed.     

Autonomic recognition of names and faces in prosopagnosia: a neuropsychological application of the Guilty Knowledge Test

A prosopagnosic was shown two sets of faces, one comprised of famous personalities, the other of family members. After he was allowed to visually inspect each face, he was given five names, one of which was correct. Skin conductance was continuously recorded. He could not identify any of the faces spontaneously, and performed at chance level when given multiple choice names. However, electrodermal responses indicated far more accurate discrimination between correct and incorrect names, suggesting that the patient "recognized" facial identity at the psychophysiological level. Neuropsychological mechanisms for this phenomenon, which in this case involve multiple visual-limbic interrelationships, are postulated. The method appears useful for studying islands of spared recognition ability in associative agnosia.     

Cerebral evoked potentials and conscious and unconscious recognition of faces: application to the study of prosopagnosia

Twelve normal subjects and a prosopagnosic patient were tested in a classification task of a random display of well-known among unknown faces. Each face was presented several times. Event-related potentials (ERP) and reaction time (RT) were studied as a function of face repetition and familiarity. For normal subjects, the greater the repetition level, the more positive ERPs were on both hemispheres: between 250 and 600 msec. Moreover, the familiarity of faces modified ERPs between 350 and 600 msec. In contrast for the patient, the greater the repetition, the more negative the ERPs were. This "negative effect" was maximum on right parieto-temporal leads and was longer for unrecognized well-known than for unknown faces. These results support a differential processing of faces as a function of their memory representations for both normal subjects and patients. They further demonstrate the existence of covert face recognition processes in prosopagnosia.     

Neural correlates of recognition memory for emotional faces and scenes

We examined the influence of emotional valence and type of item to be remembered on brain activity during recognition, using faces and scenes. We used multivariate analyses of event-related fMRI data to identify whole-brain patterns, or networks of activity. Participants demonstrated better recognition for scenes vs faces and for negative vs neutral and positive items. Activity was increased in extrastriate cortex and inferior frontal gyri for emotional scenes, relative to neutral scenes and all face types. Increased activity in these regions also was seen for negative faces relative to positive faces. Correct recognition of negative faces and scenes (hits vs correct rejections) was associated with increased activity in amygdala, hippocampus, extrastriate, frontal and parietal cortices. Activity specific to correctly recognized emotional faces, but not scenes, was found in sensorimotor areas and rostral prefrontal cortex. These results suggest that emotional valence and type of visual stimulus both modulate brain activity at recognition, and influence multiple networks mediating visual, memory and emotion processing. The contextual information in emotional scenes may facilitate memory via additional visual processing, whereas memory for emotional faces may rely more on cognitive control mediated by rostrolateral prefrontal regions.     

Paradoxical configuration effects for faces and objects in prosopagnosia

Selective impairment in recognition of faces (prosopagnosia) has been advanced as an argument for a brain module dedicated to face processing and focusing on the specific configural properties of faces. Loss of the inversion effect supposedly strengthened the argument ([10]: de Gelder B, Bachoud-Levi AC, Degos JD. Inversion superiority in visual agnosia may be common to a variety of orientation polarised objects besides faces. Vision Research, 1998;38:2855-61; [20]: Farah MJ, Wilson K, Drain H, Tanaka J. The inverted face inversion effect in prosopagnosia: Evidence for mandatory, face-specific perceptual mechanisms. Vision Research 1995b;35:2089-93). The present study of prosopagnosic patient LH reports that he has lost the normal pattern of superior performance with upright faces and objects and shows instead paradoxical inversion effect for faces but also for objects. Experiment 2 investigated whether LH's use of features based route for processing upright objects would be hindered by the whole-based encoding when processing upright objects. The data show the same context effect for objects as was found for faces. Therefore the inversion effect does not present decisive evidence for the existence of a face module. Moreover, the importance of configuration-based recognition known to be crucial for face processing, must also be taken seriously for object recognition.     

Affective impairments in binge drinking: Investigation through emotional facial expression decoding

ObjectiveBinge drinking, an excessive alcohol consumption pattern frequently observed in young people, is known to be associated with psychological and cerebral deficits. While cognitive dysfunctions have been widely investigated, emotional abilities have scarcely been explored. Such an exploration would however offer a more exhaustive understanding of the deficits associated with binge drinking, as well as of the possible transition towards alcohol-dependence.Methods46 young adults (23 binge drinkers, 12 women; 23 control participants, 12 women) were recruited among university students. They performed an emotional recognition task consisting of the visual decoding of six basic emotions (i.e. anger, contempt, disgust, fear, happiness, and sadness). Accuracy scores and detection thresholds were collected for each emotion.ResultsBinge drinkers showed lower performance than control participants for the decoding of all emotions and increased detection threshold, this later reflecting less ability to capture an emotion. Binge drinking is thus associated with a need for higher emotional intensity to perform correct detection. Moreover, these emotional difficulties appear specifically related to alcohol consumption.ConclusionThese findings reinforce previous experimental evidence of altered emotional processing among binge drinkers, and extend these results for various emotional contents. They support the hypothesis of a continuum between binge drinking and alcohol-dependence, in which massive emotional impairments have been documented. Indeed, these impairments could be involved in the onset and maintenance of excessive alcohol consumption, notably through the established relationship between emotional deficits and social distress.     

Covert recognition in acquired and developmental prosopagnosia

BACKGROUND: Some patients with prosopagnosia have covert recognition, meaning that they retain some familiarity or knowledge of facial identity of which they are not aware. OBJECTIVE:To test the hypothesis that prosopagnosic patients with right occipitotemporal lesions and impaired face perception lack covert processing, whereas patients with associative prosopagnosia and bilateral anterior temporal lesions possess it. METHODS: Eight patients with prosopagnosia were tested with a battery of four face recognition tests to determine their ability to discriminate between famous and unknown faces. RESULTS: Measures of overt familiarity revealed better residual discrimination in patients with acquired prosopagnosia than in those with the developmental form. With forced-choice methods using famous faces paired with unknown faces, no patient demonstrated covert familiarity. However, when the semantic cue of the name of the famous face was provided, covert processing was present in all five patients with acquired prosopagnosia, including the three with extensive right-sided lesions and impaired perceptual discrimination of facial configuration. Sorting unrecognized faces by occupation was also performed above chance in three of these five patients. In contrast, none of the three patients with developmental prosopagnosia had covert processing, even though two demonstrated flawless performance on similar tests of name (rather than face) recognition. Overt familiarity correlated highly with the degree of covert recognition. CONCLUSIONS: Extensive right occipitotemporal lesions with significant deficits in face perception are not incompatible with covert face processing. Covert processing is absent in developmental prosopagnosia, because this condition likely precludes the establishment of a store of accurate facial memories. The presence of covert processing correlates with the degree of residual overt familiarity, indicating that these are related phenomena.     

Training with own-race faces can improve processing of other-race faces: evidence from developmental prosopagnosia

Faces of one's own race are discriminated and recognized more accurately than faces of an other race (other-race effect - ORE). Studies have employed several methods to enhance individuation and recognition of other-race faces and reduce the ORE, including intensive perceptual training with other-race faces and explicitly instructing participants to individuate other-race faces. Unfortunately, intensive perceptual training has shown to be specific to the race trained and the use of explicit individuation strategies, though applicable to all races, can be demanding of attention and difficult to consistently employ. It has not yet been demonstrated that a training procedure can foster the automatic individuation of all other-race faces, not just faces from the race trained. Anecdotal evidence from a training procedure used with developmental prosopagnosics (DPs) in our lab, individuals with lifelong face recognition impairments, suggests that this may be possible. To further test this idea, we had five Caucasian DPs perform ten days of configural face training (i.e. attending to small spacing differences between facial features) with own-race (Caucasian) faces to see if training would generalize to improvements with other-race (Korean) faces. To assess training effects and localize potential effects to parts-based or holistic processing, we used the part-whole task using Caucasian and Korean faces (Tanaka, J. W., Kiefer, M., & Bukach, C. M. (2004). A holistic account of the own-race effect in face recognition: evidence from a cross-cultural study. Cognition, 93(1), B1-9). Results demonstrated that after training, DPs showed a disproportionate improvement in holistic processing of other-race faces compared to own-race faces, reducing their ORE. This suggests that configural training with own-race faces boosted DPs’ general configural/holistic attentional resources, which they were able to apply to other-race faces. This provides a novel method to reduce the ORE and supports more of an attentional/social-cognitive model of the ORE rather than a strictly expertise model.     

Exploring the role of motion in prosopagnosia: recognizing, learning and matching faces

HJA has been completely unable to recognize faces since suffering a stroke some 22 years ago. Previous research has shown that he is poor at judging expressions from static photographs of faces, but performs relatively normally at these judgements when presented with moving point-light patterns (Humphreys et al., 1993). Recent research with non-prosopagnosic participants has suggested a beneficial role for facial motion when recognizing familiar faces and learning new faces. Three experiments are reported that investigate the role of face motion for HJA when recognizing (Experiment 1), learning (Experiment 2) and matching faces (Experiment 3). The results indicate that HJA is unable to use face motion to explicitly recognize faces and is no better at learning names for moving faces than static ones. However, HJA is significantly better at matching moving faces for identity, an opposite pattern to that found with age-matched and undergraduate control participants. We suggest that HJA is not impaired at processing motion information but remains unable to use motion as a cue to identity.     

Impaired holistic processing of unfamiliar individual faces in acquired prosopagnosia

Prosopagnosia is an impairment at individualizing faces that classically follows brain damage. Several studies have reported observations supporting an impairment of holistic/configural face processing in acquired prosopagnosia. However, this issue may require more compelling evidence as the cases reported were generally patients suffering from integrative visual agnosia, and the sensitivity of the paradigms used to measure holistic/configural face processing in normal individuals remains unclear. Here we tested a well-characterized case of acquired prosopagnosia (PS) with no object recognition impairment, in five behavioral experiments (whole/part and composite face paradigms with unfamiliar faces). In all experiments, for normal observers we found that processing of a given facial feature was affected by the location and identity of the other features in a whole face configuration. In contrast, the patient's results over these experiments indicate that she encodes local facial information independently of the other features embedded in the whole facial context. These observations and a survey of the literature indicate that abnormal holistic processing of the individual face may be a characteristic hallmark of prosopagnosia following brain damage, perhaps with various degrees of severity.     

Discriminating Thatcherised from typical faces in a case of prosopagnosia

We report data from a prosopagnosic patient (PHD), and aged-matched control participants, from experiments where participants categorised individually presented emotional faces (Experiment 1) and Thatcherised (from typical) faces (Experiment 2). In Experiment 2 participants also discriminated between simultaneously presented Thatcherised and typical faces. PHD was at chance categorising Thatcherised from typical faces. He was, however, able to discriminate between Thatcherised and typical faces, and partially able to categorise emotional faces. The results are discussed in terms of a loss of configural processing but preserved feature processing in PHD. The loss of configural processing impacts his categorisation of Thatcherised and typical faces, and his emotion processing, while his preserved feature processing supports his ability to categorise some emotional faces and his ability to discriminate between Thatcherised and typical faces.     

The contribution of anterior and posterior regions of the right hemisphere to the recognition of emotional faces

To investigate the contribution of posterior and anterior parts of the right hemisphere (RH) to emotional facial recognition, we studied 11 participants with anterior strokes of the right hemisphere (ASRH), 16 patients with posterior strokes of the right hemisphere (PSRH), and 31 normal controls. All individuals were right-handed and nondemented. The ability to recognize emotional facial expressions was assessed by using Ekman and Friesen's (1976) Pictures of Facial Affect. Analysis revealed that both groups of patients presented with an impaired recognition of emotional faces. However, patients with PSRH were able to identify facial expressions better than participants with ASRH. In comparison to participants sustaining PSRH, patients with ASRH were particularly impaired on recognizing faces of negative valence. Thus, our results suggest that anterior parts of the RH seem to play an important role in the recognition of emotional facial expressions.     

Passing faces: sequence-dependent variations in the perceptual processing of emotional faces

There is broad evidence that contextual factors influence the processing of emotional facial expressions. Yet temporal-dynamic aspects, inter alia how face processing is influenced by the specific order of neutral and emotional facial expressions, have been largely neglected. To shed light on this topic, we recorded electroencephalogram from 168 healthy participants while they performed a gender-discrimination task with angry and neutral faces. Our event-related potential (ERP) analyses revealed a strong emotional modulation of the N170 component, indicating that the basic visual encoding and emotional analysis of a facial stimulus happen, at least partially, in parallel. While the N170 and the late positive potential (LPP; 400–600 ms) were only modestly affected by the sequence of preceding faces, we observed a strong influence of face sequences on the early posterior negativity (EPN; 200–300 ms). Finally, the differing response patterns of the EPN and LPP indicate that these two ERPs represent distinct processes during face analysis: while the former seems to represent the integration of contextual information in the perception of a current face, the latter appears to represent the net emotional interpretation of a current face.     

Dissociations of face and object recognition in developmental prosopagnosia

Neuropsychological studies with patients suffering from prosopagnosia have provided the main evidence for the hypothesis that the recognition of faces and objects rely on distinct mechanisms. Yet doubts remain, and it has been argued that no case demonstrating an unequivocal dissociation between face and object recognition exists due in part to the lack of appropriate response time measurements (Gauthier et al., 1999). We tested seven developmental prosopagnosics to measure their accuracy and reaction times with multiple tests of face recognition and compared this with a larger battery of object recognition tests. For our systematic comparison, we used an old/new recognition memory paradigm involving memory tests for cars, tools, guns, horses, natural scenes, and houses in addition to two separate tests for faces. Developmental prosopagnosic subjects performed very poorly with the face memory tests as expected. Four of the seven prosopagnosics showed a very strong dissociation between the face and object tests. Systematic comparison of reaction time measurements for all tests indicates that the dissociations cannot be accounted for by differences in reaction times. Contrary to an account based on speed accuracy tradeoffs, prosopagnosics were systematically faster in nonface tests than in face tests. Thus, our findings demonstrate that face and nonface recognition can dissociate over a wide range of testing conditions. This is further support for the hypothesis that face and nonface recognition relies on separate mechanisms and that developmental prosopagnosia constitutes a disorder separate from developmental agnosia.     

Impaired recognition and expression of emotional prosody in schizophrenia: review and meta-analysis

BACKGROUND: Deficits in emotion processing may be one of the most pervasive disturbances in schizophrenia that may contribute to social isolation. In this report we focus on vocal emotion processing. This function bears upon two corner stones of social functioning, language and emotion, which have both been found to be impaired in schizophrenia. METHODS: We used meta-analysis to integrate findings of studies published between 1980 and June 2007 on perception of emotional prosody in schizophrenia. 17 studies provided sufficient information to be included. A mean weighted effect size was computed in the random effects model. Publication bias was tested using funnel plots and fail-safe number of studies. Seven studies were included in an analysis on the expression (i.e. production) of emotional prosody in schizophrenia. RESULTS: A significant and stable mean weighted effect size was found for the perception of emotional prosody, d=-1.24, 95% CI=-1.55 to -0.93. The effect was also found in the early stages of the illness. Expression of emotional prosody was also significantly impaired, d=-1.11, 95% CI=-1.78 to -0.43. CONCLUSIONS: Results indicate that individuals with schizophrenia are impaired in the perception and expression of emotional prosody, with a large effect size. As a growing body of evidence shows that impaired social cognition in schizophrenia may be an important predictor of social outcome, training programs that aim at the recognition of emotional prosody should be developed.     

利用情绪面孔嵌合图形研究精神分裂症的注意偏向

目的探讨精神分裂症患者的注意偏向情况。方法利用情绪面孔嵌合图形试验和线段等分试验对年龄、文化程度、简易精神状态量表(mini-mental state examination,MMSE)评分等相匹配的32例精神分裂症患者和32名正常对照进行测试。结果精神分裂症患者在本顿面孔识别试验中和对照组差异无统计学意义(t=-0.85,P>0.05)。情绪(喜)面孔嵌合试验和20 cm线段等分试验,患者组的偏移率均比对照组高[-18.75(-31.25,-6.25)vs.-12.50(-23.44,4.69);-1.40(-2.65,-0.93)vs.-0.45(-1.50,0.30)],差异有统计学意义。患者组的情绪(喜)面孔嵌合和线段等分之间的偏移率相关(r=0.68,P<0.01)。结论精神分裂症患者在情绪(喜)面孔嵌合试验中注意左偏,这与线段等分试验结果相同,提示患者右侧空间注意受损,可能与左侧脑半球功能障碍有关。     

Facial expression and emotional face recognition in schizophrenia and depression

Summary Twenty-three acute schizophrenics, 21 acute major depressives (Research Diagnostic Criteria), and 15 normal controls participated in a study on facial expression and emotional face recognition. Under clinical conditions, spontaneous facial expression was assessed according to the affective flattening section of the Scale for the Assessment of Negative Symptoms. Under experimental laboratory conditions involuntary (emotioneliciting interview) and voluntary facial expression (imitation and simulation of six basic emotions) were recorded on videotape, from which a raterbased analysis of intensity or correctness of facial activity was obtained. Emotional face recognition was also assessed under experimental conditions using the same stimulus material. All subjects were assessed twice (within 4 weeks), controlling for change of the psychopathological status in the patient groups. In schizophrenics, neuroleptic drug influence was controlled by random allocation to treatment with either haloperidol or perazine. The main findings were that schizophrenics and depressives are characterized by different quantitative, qualitative, and temporal patterns of affect-related dysfunctions. In particular, schizophrenics demonstrated a trait-like deficit in affect recognition and in their spontaneous and voluntary facial activity, irrespective of medication, drug type and dosage, or extrapyramidal side-effects. In depressives a stable deficit could be demonstrated only in their involuntary expression under emotion-eliciting interview conditions, whereas in the postacute phase a reduction in their voluntary expression became apparent. Differences in patterns of affect-related behavioral deficits may reflect dysfunctions in different underlying psychobiological systems.