人类躯体与人类面孔相似:是由各个部位按照一定的空间关系组成,并且是对称的。它也能提供个体身份和行为方式等信息,如年龄、性别、意图、情感状态等。它与面孔相辅相成,共同促成对个体身份的辨别。躯体知觉是指大脑对进入视觉加工系统中的人类躯体刺激的侦察,感知或识别。躯体知觉应当如面孔知觉研究一样受到更多的关注。文章概述、评价了与躯体知觉相关的认知神经研究,着重介绍了躯体知觉的认知和神经机制,并提出了一些值得进一步研究的问题。

Neural mechanisms of object recognition, especially the neural mechanisms of novel artificial objects expertise recognition are an important window to investigate the brain plasticity. In current research, the event-related potential was used to investigate the formation process of non-face object inversion effect. Two kinds of participants were selected: (1) Experts of a certain kinds of object recognition without any arbitrary trained by experimenter, such ability formed in daily life; (2) novice participant who recognize novel artificial objects with or without arbitrary training. Through manipulating the magnitude of inversion effect in a serial experiment, we aim to dissociate specific ERP components of expertise recognition and explore the brain plasticity of object recognition. The whole project tries to propose our own model which can explain the relationship between the level of experience from a certain orientation of object and the selection of processing strategies in object recognition. The result of this project also could provide the exact evidence of cognitive neuroscience to support and improve theory of configural processing continuum.

面孔倒置效应是指,个体对倒置面孔的再认成绩显著低于对正立面孔的再认成绩,而且,与普通物体的倒置效应相比,面孔的倒置效应更大。研究者们针对面孔倒置效应提出了多种理论假说,两种主要的理论解释是:第一,倒置面孔破坏了面孔的结构特征,影响了面孔的整体加工,所以,个体对倒置面孔的再认成绩较差;第二,眼睛在面孔加工中起重要作用,尤其在倒置面孔中的作用更明显,使得倒置面孔N170波幅较高。ERP和fMRI研究提示,未来研究需要进一步明确眼睛、注意等在面孔倒置效应中的作用。

面孔信息的分类方法一直复杂多样,相关研究数据丰富,但所用概念混杂.构形加工与特征加工作为使用最频繁的分类方法,其可靠性越来越受研究者们关注.从近40年来的相关文献中选择引用率高的文献做参考,遵循不同研究方法相互印证的原则分析数据,提出构形加工与特征加工的区分是面孔识别中重要并且可靠的加工类型划分,但确认两者在知觉加工上的先后关系以及在个体发展上的先后顺序尚缺乏稳定一致性的实验依据.

The Body Inversion Effect (BIE; reduced visual discrimination performance for inverted compared to upright bodies) suggests that bodies are visually processed configurally; however, the specific importance of head posture information in the BIE has been indicated in reports of BIE reduction for whole bodies with fixed head position and for headless bodies. Through measurement of gaze patterns and investigation of the causal relation of fixation location to visual body discrimination performance, the present study reveals joint contributions of feature and configuration processing to visual body discrimination. Participants predominantly gazed at the (body-centric) upper body for upright bodies and the lower body for inverted bodies in the context of an experimental paradigm directly comparable to that of prior studies of the BIE. Subsequent manipulation of fixation location indicates that these preferential gaze locations causally contributed to the BIE for whole bodies largely due to the informative nature of gazing at or near the head. Also, a BIE was detected for both whole and headless bodies even when fixation location on the body was held constant, indicating a role of configural processing in body discrimination, though inclusion of the head posture information was still highly discriminative in the context of such processing. Interestingly, the impact of configuration (upright and inverted) to the BIE appears greater than that of differential preferred gaze locations.

Similar to faces, discrimination of human bodies is much worse for inverted than upright bodies. Interestingly, this body inversion effect disappears for headless bodies, which implies a critical role for the head in the generation of this effect. Previous studies have shown that the face inversion effect is mediated by the fusiform face-selective area. Given the central role the head plays in the behavioral body inversion effect, here we asked whether the body inversion effect is mediated by face-selective or body-selective brain areas. In two event-related fMR-adaptation experiments, we measured the response of category-selective occipito-temporal areas to pairs of upright or inverted bodies that were either same or different in posture. The first experiment presented whole bodies, while the second used headless bodies. For all body stimuli internal facial features were covered with a gray ellipsoid. Body-selective areas showed a higher response to inverted than upright bodies, but a similar adaptation effect (higher response to different than same pairs) for the two orientations, suggesting similar discrimination for upright and inverted bodies. This pattern was found for both whole bodies and headless bodies. In contrast, face-selective areas showed adaptation effect to upright but not inverted bodies. This pattern was found for whole bodies but not for headless bodies, where there was no adaptation for both orientations. Response of object-general areas (LOC) was higher for inverted than upright bodies and showed no adaptation effect for both orientations. Thus, only the response of the face-selective regions was consistent with the behavioral body inversion effect in that it shows discrimination for upright but not inverted bodies, for whole but not for headless bodies. We conclude that the body inversion effect is not mediated by body processing mechanisms but by face or head processing mechanisms.

Behavioral studies suggested that bodies are represented as wholes rather than in a part-based manner. However, neural selectivity for body stimuli is found for both whole bodies and body parts. It is therefore undetermined whether the neural representation of bodies is configural or part-based. We used functional MRI to test the role of first-order configuration on body representation in the human occipital-temporal cortex by comparing the response to a whole body versus the sum of its parts. Results show that body-selective areas, whether defined by selectivity to headless bodies or body parts, preferred whole bodies over their sum of parts and successfully decoded body configuration. This configural representation was specific to body stimuli and not found for faces. In contrast, general object areas showed no preference for wholes over parts and decoded the configuration of both bodies and faces. Finally, whereas effects of inversion on configural face representation were specific to face-selective mechanisms, effects of body inversion were not unique to body-selective mechanisms. We conclude that the neural representation of body parts is strengthened by their arrangement into an intact body, thereby demonstrating a central role of first-order configuration in the neural representation of bodies in their category-selective areas.

It has been suggested that face recognition is primarily based on configural information, with featural information playing little or no role. We investigated this idea by comparing the prototype effect for face prototypes that emphasized either featural or configural processing. In Experiment 1, participants showed a tendency to commit false alarms in response to nonstudied prototypes, and this tendency was equivalent for featural and configural prototypes. Experiment 2 replicated this finding, and provided support for the assumption that the two types of prototypes differed in terms of featural and configural processing: Face inversion eliminated the prototype effect for configural prototypes but not for featural prototypes. These results suggest that both featural and configural processing make important contributions to face recognition, and that their effects are dissociable.

The ability to derive the facing direction of a spatially scrambled point-light walker relies on the motions of the feet and is impaired if they are inverted. We exploited this local inversion effect in three experiments that employed novel stimuli derived from only fragments of full foot trajectories. In Experiment 1, observers were presented with stimuli derived from a single fragment or a pair of counterphase fragments of the foot trajectory of a walker in a direction discrimination task. We show that direction can be retrieved for displays as short as 100 ms and is retrieved in an orientation-dependent manner only for stimuli derived from the paired fragments. In Experiment 2, we investigated direction retrieval from stimuli derived from paired fragments of other foot motions. We show that the inversion effect is correlated with the difference in vertical acceleration between the constituent fragments of each stimulus. In Experiment 3, we compared direction retrieval from the veridical walker stimuli with stimuli that were identical but had accelerations removed. We show that the inversion effect disappears for the stimuli containing no accelerations. The results suggest that the local inversion effect is carried by accelerations contained in the foot motions.

The "body inversion effect" refers to superior recognition of upright than inverted images of the human body and indicates typical configural processing. Previous research by Reed et al. using static images of the human body shows that people with autism fail to demonstrate this effect. Using a novel task in which adults, adolescents with autism, and typically developing adolescents judged whether walking stick figures-created from biological motion recordings and shown at seven orientations between 0 and 180-were normal or distorted, this study shows clear effects of stimulus inversion. Reaction times and "inverse efficiency" increased with orientation for normal but not distorted walkers, and sensitivity declined with rotation from upright for all groups. Notably, the effect of stimulus inversion was equally detrimental to both groups of adolescents suggesting intact configural processing of the body in motion in autism spectrum disorder.

Recent studies of monkeys and humans have identified several brain regions that respond to bodies. Researchers have so far mainly addressed the same questions about bodies and bodily expressions that are already familiar from three decades of face and facial expression studies. Our present goal is to review behavioral, electrophysiological and neurofunctional studies on whole body and bodily expression perception against the background of what is known about face perception. We review all currently available evidence in more detail than done so far, but we also argue for a more theoretically motivated comparison of faces and bodies that reflects some broader concerns than only modularity or category specificity of faces or bodies.

08 2016 Elsevier B.V. Growing evidence suggests that the brain processes bodies distinctively from other stimuli, but little research has addressed whether visual body perception is modulated by the observer's thoughts and feelings about their own body. The present study thus investigated the relationship between body image and electrophysiological signatures of body perception, with the aim of identifying potential biomarkers of body image disturbances. Occipito-parietal (P1 and N1) and fronto-central (VPP) processing of body and non-body stimuli were assessed in 29 weight-restored eating disordered (ED) women and compared to 27 healthy controls. Rapid early visual processing was seen in the ED group, as the entire P1-N1 complex unfolded significantly earlier compared to controls. ED women also showed a gender-sensitive response to other women's bodies over N1 and VPP components. Such gender-sensitivity was not evident in controls. Moreover, ERP effects correlated with scores on the Eating Disorder Inventory-II (EDI-2), indicating a close link between the observers’ ED symptomatology, including body image, and the visual analysis of human bodies during very early stages of cortical processing. The temporal dynamics of visual body perception may therefore serve as potential neural markers for the identification of ED symptomatology in ‘at risk’ populations.

Human beings possess a remarkable ability to recognise familiar faces quickly and without apparent effort. In spite of this facility, the mechanisms of visual recognition remain tantalizingly obscure. An experiment is reported in which image processing equipment was used to displace slightly the features of a set of original facial images to form groups of modified images. Observers were then required to indicate whether they were being shown the "original" or a "modified" face, when shown one face at a time on a TV monitor screen. Memory reinforcement was provided by displaying the original face at another screen position, between presentations. The data show, inter alia, the very high significance of the vertical positioning of the mouth, followed by eyes, and then the nose, as well as high sensitivity to close-set eyes, coupled with marked insensitivity to wide-set eyes. Implications of the results for the use of recognition aids such as Identikit and Photofit are briefly discussed.

Although holistic processing has been documented extensively for upright faces, it is unclear whether it occurs for other visual categories with more extensive substructure, such as body postures. Like faces, body postures have high social relevance, but they differ in having fine-grain organization not only of basic parts (e.g., arm) but also subparts (e.g., elbow, wrist, hand). To compare holistic processing for whole bodies and body parts, we employed a novel stereoscopic depth manipulation that creates either the percept of a whole body occluded by a set of bars, or of segments of a body floating in front of a background. Despite sharing low-level visual properties, only the stimulus perceived as being behind bars should be holistically “filled in” via amodal completion. In two experiments, we tested for better identification of individual body parts within the context of a body versus in isolation. Consistent with previous findings, recognition of body parts was better in the context of a whole body when the body was amodally completed behind occluders. However, when the same bodies were perceived as floating in strips, performance was significantly worse, and not significantly different, from that for amodally completed parts, supporting holistic processing of body postures. Intriguingly, performance was worst for parts in the frontal depth condition, suggesting that these effects may extend from gross body organization to a more local level. These results provide suggestive evidence that holistic representations may not be “all-or-none,” but rather also operate on body regions of more limited spatial extent.

The effects of short-term learning on memory for inverted, contrast-reversed and upright faces were investigated using event-related potentials (ERPs) in a target/nontarget discrimination task following a learning phase of the target. Subjects were equally accurate for all three face types although responding more slowly to inverted and negative faces compared to upright faces. Face type affected both early ERP components P1 and N170, and long-latency components at frontal and parietal sites, reflecting the difficulty of processing inverted faces. Different effects of face type were found for P1 and N170 latencies and amplitudes, suggesting face processing could start around 100–120 ms and is sensitive to facial configuration. Repetition effects were also found on both early and long-latency components. Reduced N170 latency and amplitude for repeated targets are likely due to perceptual priming. Repetition effects on the N250 were delayed for inverted and negative faces, suggesting delayed access to stored facial representations for these formats. Increased frontopolar positivity at 250–300 ms and parietal positivity from 300 to 500 ms reflected familiarity ‘old–new’ repetition effects that were of similar magnitude for all three face types, indexing the accurate recognition of all faces. Thus, while structural encoding was disrupted by inversion and contrast-reversal, the learning phase was sufficient to abolish the effects of these configural manipulations behaviourally; all three face types were equally well recognised and this was reflected as equally large parietal old–new effects.

Abstract The ERP component N170 is face-sensitive, yet its specificity for faces is controversial. We recorded ERPs while subjects viewed upright and inverted faces and seven object categories. Peak, topography and segmentation analyses were performed. N170 was earlier and larger to faces than to all objects. The classic increase in amplitude and latency was found for inverted faces on N170 but also on P1. Segmentation analyses revealed an extra map found only for faces, reflecting an extra cluster of activity compared to objects. While the N1 for objects seems to reflect the return to baseline from the P1, the N170 for faces reflects a supplement activity. The electrophysiological 'specificity' of faces could lie in the involvement of extra generators for face processing compared to objects and the N170 for faces seems qualitatively different from the N1 for objects. Object and face processing also differed as early as 120 ms.

Is the human mind/brain composed of a set of highly specialized components, each carrying out a specific aspect of human cognition, or is it more of a general-purpose device, in which each component participates in a wide variety of cognitive processes? For nearly two centuries, proponents of specialized organs or modules of the mind and brain—from the phrenologists to Broca to Chomsky and Fodor—have jousted with the proponents of distributed cognitive and neural processing—from Flourens to Lashley to McClelland and Rumelhart. I argue here that research using functional MRI is beginning to answer this long-standing question with new clarity and precision by indicating that at least a few specific aspects of cognition are implemented in brain regions that are highly specialized for that process alone. Cortical regions have been identified that are specialized not only for basic sensory and motor processes but also for the high-level perceptual analysis of faces, places, bodies, visually presented words, and even for the very abstract cognitive function of thinking about another person's thoughts. I further consider the as-yet unanswered questions of how much of the mind and brain are made up of these functionally specialized components and how they arise developmentally.

Abstract A group of European experts was commissioned to establish guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS) from evidence published up until March 2014, regarding pain, movement disorders, stroke, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy, consciousness disorders, tinnitus, depression, anxiety disorders, obsessive-compulsive disorder, schizophrenia, craving/addiction, and conversion. Despite unavoidable inhomogeneities, there is a sufficient body of evidence to accept with level A (definite efficacy) the analgesic effect of high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the pain and the antidepressant effect of HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC). A Level B recommendation (probable efficacy) is proposed for the antidepressant effect of low-frequency (LF) rTMS of the right DLPFC, HF-rTMS of the left DLPFC for the negative symptoms of schizophrenia, and LF-rTMS of contralesional M1 in chronic motor stroke. The effects of rTMS in a number of indications reach level C (possible efficacy), including LF-rTMS of the left temporoparietal cortex in tinnitus and auditory hallucinations. It remains to determine how to optimize rTMS protocols and techniques to give them relevance in routine clinical practice. In addition, professionals carrying out rTMS protocols should undergo rigorous training to ensure the quality of the technical realization, guarantee the proper care of patients, and maximize the chances of success. Under these conditions, the therapeutic use of rTMS should be able to develop in the coming years. Copyright 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Adults' expert face recognition has been attributed to configural processing. Based on behavioural and neural marker tasks and developmental studies, we argue that configural processing encompasses three distinct processes

The present study aimed to further explore the mechanisms underlying the perception of human body shapes. Behavioral and electrophysiological inversion effects were studied for human bodies with and without heads and for animal bodies (cats, dogs, and birds). Recognition of human bodies (with heads) was adversely affected by stimulus inversion, and the N170 had longer latencies and higher amplitudes for inverted compared to upright human bodies. Human body shapes presented without heads yielded the opposite result pattern. The data for animal bodies did not yield consistent effects. Taken together, the present findings suggest that human bodies might be processed by specialized cortical mechanisms which are at least partly dissociable from mechanisms involved in object or face processing.

We investigated effects of attentional load and inversion on event-related potentials to body or face distractors. Participants performed demanding (high load) or less demanding (low load) unrelated letter-search tasks. Bodies and faces were intact (Experiment 1) or without heads or eyes (Experiment 2). We measured prominent P100, N170, and late occipito-temporal negative (LNC) components. N170 to bodies had smaller and more anterior maxima than faces. N170 to intact bodies and faces was increased by inversion, relatively independently of load. Inversion effects were dramatically reduced for headless bodies, and even reversed for eyeless faces. Load effects were most prominent in LNC, with enhanced negativity under low load. We suggest that N170 reflects mandatory, category-specific initial distractor encoding in body- or face-sensitive cortical areas, a process which may depend on interactive encoding of hierarchical cues (bodies, heads, eyes). By contrast, LNC mainly reflects residual capacity allocated to extended processing of task-irrelevant distractors.

How does one perceive groups of people? It is known that functionally interacting objects (e.g., a glass and a pitcher tilted as if pouring water into it) are perceptually grouped. Here, we showed that processing of multiple human bodies is also influenced by their relative positioning. In a series of categorization experiments, bodies facing each other (seemingly interacting) were recognized more accurately than bodies facing away from each other (noninteracting). Moreover, recognition of facing body dyads (but not nonfacing body dyads) was strongly impaired when those stimuli were inverted, similar to what has been found for individual bodies. This inversion effect demonstrates sensitivity of the visual system to facing body dyads in their common upright configuration and might imply recruitment of configural processing (i.e., processing of the overall body configuration without prior part-by-part analysis). These findings suggest that facing dyads are represented as one structured unit, which may be the intermediate level of representation between multiple-object (body) perception and representation of social actions.

The human body, like the human face, is a rich source of socially relevant information about other individuals. Evidence from studies of both humans and non-human primates points to focal regions of the higher-level visual cortex that are specialized for the visual perception of the body. These body-selective regions, which can be dissociated from regions involved in face perception, have been implicated in the perception of the self and the 'body schema', the perception of others' emotions and the understanding of actions.

Autism has been associated with atypical face and configural processing, as indicated by the lack of a face inversion effect (better recognition of upright than inverted faces). We investigated whether such atypical processing was restricted to the face or extended to social information found in body postures. An inversion paradigm compared recognition of upright and inverted faces, body postures, and houses. Typical adults demonstrated inversion effects for both faces and body postures, but adults with autism demonstrated only a face inversion effect. Adults with autism may not have a configural processing deficit per se, but instead may have strategies for recognizing faces not used for body postures. Results have implications for therapies employing training in imitation and body posture perception.

Like faces, body postures are susceptible to an inversion effect in untrained viewers. The inversion effect may be indicative of configural processing, but what kind of configural processing is used for the recognition of body postures must be specified. The information available in the body stimulus was manipulated. The presence and magnitude of inversion effects were compared for body parts, scrambled bodies, and body halves relative to whole bodies and to corresponding conditions for faces and houses. Results suggest that configural body posture recognition relies on the structural hierarchy of body parts, not the parts themselves or a complete template match. Configural recognition of body postures based on information about the structural hierarchy of parts defines an important point on the configural processing continuum, between recognition based on first-order spatial relations and recognition based on holistic undifferentiated template matching.

Abstract Face recognition is thought to rely on specific mechanisms underlying a perceptual bias toward processing faces as undecomposable wholes. This face-specific "holistic processing" is commonly quantified using 3 measures: the inversion, part-whole, and composite effects. Consequently, many researchers assume that these 3 effects measure the same cognitive mechanism(s) and these mechanisms contribute to the wide range of individual differences seen in face recognition ability. We test these assumptions in a large sample (N = 282), with individual face recognition abilities measured by the well-validated Cambridge Face Perception Test. Our results provide little support for either assumption. The small to nonexistent correlations among inversion, part-whole, and composite effects (correlations between -.03 and .28) fail to support the first assumption. As for the second assumption, only the inversion effect moderately predicts face recognition (r = .42); face recognition was weakly correlated with the part-whole effect (r = .25) and not correlated with the composite effect (r = .04). We rule out multiple artifactual explanations for our results by using valid tasks that produce standard effects at the group level, demonstrating that our tasks exhibit psychometric properties suitable for individual differences studies, and demonstrating that other predicted correlations (e.g., between face perception measures) are robust. Our results show that inversion, part-whole, and composite effects reflect distinct perceptual mechanisms, and we argue against the use of the single, generic term holistic processing when referring to these effects. Our results also question the contribution of these mechanisms to individual differences in face recognition. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Prosopagnosia is a deficit in face recognition in the presence of relatively normal object recognition. Together with older lesion studies, recent brain-imaging results provide evidence for the closely related representations of faces and objects and, more recently, for brain areas sensitive to faces and bodies. This evidence raises the issue of whether developmental prosopagnosics may also have an impairment in encoding bodies. We investigated the first stages of face, body, and object perception in four developmental prosopagnosics by comparing event-related potentials to canonically and upside-down presented stimuli. Normal configural encoding was absent in three of four developmental prosopagnosics for faces at the P1 and for both faces and bodies at the N170 component. Our results demonstrate that prosopagnosics do not have this normal processing routine readily available for faces or bodies. A profound face recognition deficit characteristic of developmental prosopagnosia may not necessarily originate in a category-specific face recognition deficit in the initial stages of development. It may also have its roots in anomalous processing of the configuration, a visual routine that is important for other stimuli besides faces. Faces and bodies trigger configuration-based visual strategies that are crucial in initial stages of stimulus encoding but also serve to bootstrap the acquisition of more feature-based visual skills that progressively build up in the course of development.

It has been estimated that one out of forty people in the general population suffer from congenital prosopagnosia (CP), a neurodevelopmental disorder characterized by difficulty identifying people by their faces. CP involves impairment in recognising faces, although the perception of non-face stimuli may also be impaired. Given that social interaction does not only depend on face processing, but also the processing of bodies, it is of theoretical importance to ascertain whether CP is also characterised by body perception impairments. Here, we tested eleven CPs and eleven matched control participants on the Body Identity Recognition Task (BIRT), a forced-choice match-to-sample task, using stimuli that require processing of body, not clothing, specific features. Results indicated that the group of CPs was as accurate as controls on the BIRT, which is in line with the lack of body perception complaints by CPs. However the CPs were slower than controls, and when accuracy and response times were combined into inverse efficiency scores (IES), the group of CPs were impaired, suggesting that the CPs could be using more effortful cognitive mechanisms to be as accurate as controls. In conclusion, our findings demonstrate CP may not generally be limited to face processing difficulties, but may also extend to body perception

Extensive research has focused on face recognition, and much is known about this topic. However, much of this work seems to be based on an assumption that faces are the most important aspect of person recognition. Here we test this assumption in two experiments. We show that when viewers are forced to choose, they do use the face more than the body, both for familiar (trained) person recognition and for unfamiliar person matching. However, we also show that headless bodies are recognized and matched with very high accuracy. We further show that processing style may be similar for faces and bodies, with inversion effects found in all cases (bodies with heads, faces alone and bodies alone), and evidence that mismatching bodies and heads causes interference. We suggest that recent findings of no inversion effect when stimuli are headless bodies may have been obtained because the stimuli led viewers to focus on nonbody aspects (e.g., clothes) or because pose and identity tasks led to somewhat different processing. Our results are consistent with holistic processing for bodies as well as faces.

A recent event-related potential (ERP) study (Thierry G., Martin, C.D., Downing, P., Pegna, A.J. 2007. Controlling for interstimulus perceptual variance abolishes N170 face selectivity. Nature Neuroscience, 10, 505–11) claimed that the larger occipito-temporal N170 response to pictures of faces than other categories – the N170 effect – is due to a methodological artifact in stimulus selection, specifically, a greater interstimulus physical variance between pictures of objects than faces in previous ERP studies which, when controlled, eliminates this N170 effect. This statement casts doubts on the validity of the conclusions reached by a whole tradition of electrophysiological experiments published over the past 15 years and questions the very interest of using the N170 to probe the time course of face processes in the human brain. Here we claim that this physical variance factor is ill-defined by Thierry et al. and cannot account for previous observations of a smaller N170 amplitude to nonface objects than faces without latency increase and component “smearing”. Most importantly, this factor was controlled in previous studies that reported robust N170 effects. We demonstrate that the absence of N170 effect in the study of Thierry et al. is due to methodological flaws in the reported experiments, most notably measuring the N170 at the wrong electrode sites. Moreover, the authors attributed a modulation of N170 amplitude in their study to a differential interstimulus physical variance while it probably reflects a biased comparison of different quality sets of individual images. Here, by taking Thierry et al.’s study as an exemplar case of what should be done in ERP research of visual categorization processes, we provide clarifications on a number of methodological and theoretical issues about the N170 and its largest amplitude to faces. More generally, we discuss the potential role of differential visual homogeneity of object categories as well as low-level visual properties versus high-level visual processes in accounting for early face-preferential responses and the question of the speed at which visual stimuli are categorized as faces. This survey of the literature points to the N170 as a critical event in the time course of face processes in the human brain.

Abstract Human occipital-temporal cortex features several areas sensitive to faces, presumably forming the biological substrate for face perception. To date, there are piecemeal insights regarding the functional organization of these regions. They have come, however, from studies that are far from homogeneous with regard to the regions involved, the experimental design, and the data analysis approach. In order to provide an overall view of the functional organization of the face-sensitive areas, it is necessary to conduct a comprehensive study that taps into the pivotal functional properties of all the face-sensitive areas, within the context of the same experimental design, and uses multiple data analysis approaches. In this study, we identified the most robustly activated face-sensitive areas in bilateral occipital-temporal cortices (i.e., AFP, aFFA, pFFA, OFA, pcSTS, pSTS) and systemically compared their regionally averaged activation and multivoxel activation patterns to 96 images from 16 object categories, including faces and non-faces. This condition-rich and single-image analysis approach critically samples the functional properties of a brain region, allowing us to test how two basic functional properties, namely face-category selectivity and face-exemplar sensitivity are distributed among these regions. Moreover, by examining the correlational structure of neural responses to the 96 images, we characterize their interactions in the greater face-processing network. We found that (1) r-pFFA showed the highest face-category selectivity, followed by l-pFFA, bilateral aFFA and OFA, and then bilateral pcSTS. In contrast, bilateral AFP and pSTS showed low face-category selectivity; (2) l-aFFA, l-pcSTS and bilateral AFP showed evidence of face-exemplar sensitivity; (3) r-OFA showed high overall response similarities with bilateral LOC and r-pFFA, suggesting it might be a transitional stage between general and face-selective information processing; (4) r-aFFA showed high face-selective response similarity with r-pFFA and r-OFA, indicating it was specifically involved in processing face information. Results also reveal two properties of these face sensitive regions across the two hemispheres: (1) the averaged left intra-hemispheric response similarity for the images was lower than the averaged right intra-hemispheric and the inter-hemispheric response similarity, implying convergence of face processing towards the right hemisphere, and (2) the response similarities between homologous regions in the two hemispheres decreased as information processing proceeded from the early, more posterior, processing stage (OFA), indicating an increasing degree of hemispheric specialization and right hemisphere bias for face information processing. This study contributes to an emerging picture of how faces are processed within the occipital and temporal cortex.

Objective: Intact faces and bodies elicit two prominent electrophysiological components (P100 and N170). The N170 is thought to be related to the structural encoding and configural processing of faces and bodies. The aim of the present study was to investigate whether intact faces and bodies as well as scrambled faces and bodies elicit the same component. This would imply that similar as faces, bodies are encoded as a whole.Methods: We used a matching to sample task and two manipulations validated as an assessment of configural processing in previous studies: the inversion effect and intact versus scrambled stimulus presentation.Results: For both categories, performance was better for intact compared to scrambled stimuli. Additionally, stimulus distortion seems to abolish the body but not the face inversion effect. On the electrophysiological level, we found enhanced N170 amplitudes for intact faces and bodies compared to scrambled stimuli. The opposite pattern engaged in the time-window of the P100. Furthermore, for the N170 we observed an inversion effect for intact but not scrambled bodies.Conclusions: First-order relational information are important for the perception of bodies and might be processed in the N170 time-window. Disrupting this information interacts with the inversion effect.Significance: The current data suggest that faces and bodies might be processed by distinct mechanisms as the experimental manipulation affected faces in a different way than bodies. (C) 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The current study aimed to explore the functional magnetic resonance (fMR)-adaption effect by presenting intact and scrambled headless bodies and faces. This fMR-adaption paradigm allows investigating processing specificity in distinct brain areas by comparing the blood-oxygen-level-dependent (BOLD) signal related to the presentation of same or different pairs of bodies. There is clear evidence that we prefer whole bodies compared to the sum of their parts. This effect refers to a subtype of configural processing termed first-order relational information. The preference for whole bodies seems to be associated with activation pattern in body-sensitive brain regions. However, it remains unclear until now, which cortical area exactly mediates this preference. In the present study, we investigated whether there are neuronal populations that show a selective adaption to whole bodies compared to the sum of their parts. The right fusiform body area (FBA) showed a preference for whole bodies compared to the sum of their parts as the right and left fusiform face area showed a preference for whole faces compared to the sum of their parts. Thus, the present data support the idea that configural body and face processing is mediated by the fusiform gyrus. The current data further support the view that bodies are a special stimulus class with specific characteristics which are processed in body-sensitive brain areas.

The rapid visual detection of other people in our environment is an important first step in social cognition. Here we provide evidence for selective sensitivity of the human visual system to upright depictions of conspecifics. In a series of seven experiments, we assessed the impact of stimulus inversion on the detection of person silhouettes, headless bodies, faces and other objects from a wide range of animate and inanimate control categories. We used continuous flash suppression (CFS), a variant of binocular rivalry, to render stimuli invisible at the beginning of each trial and measured the time upright and inverted stimuli needed to overcome such interocular suppression. Inversion strongly interfered with access to awareness for human faces, headless human bodies, person silhouettes, and even highly variable body postures, while suppression durations for control objects were not (inanimate objects) or only mildly (animal faces and bodies) affected by inversion. Furthermore, inversion effects were eliminated when the normal body configuration was distorted. The absence of strong inversion effects in a binocular control condition not involving interocular suppression suggests that non-conscious mechanisms mediated the effect of inversion on body and face detection during CFS. These results indicate that perceptual mechanisms that govern access to visual awareness are highly sensitive to the presence of conspecifics.

The present study investigated the neural correlates of perceiving human bodies. Focussing on the N170 as an index of structural encoding, we recorded event-related potentials (ERPs) to images of bodies and faces (either neutral or expressing fear) and objects, while subjects viewed the stimuli presented either upright or inverted. The N170 was enhanced and delayed to inverted bodies and faces, but not to objects. The emotional content of faces affected the left N170, the occipito-parietal P2, and the fronto-central N2, whereas body expressions affected the frontal vertex positive potential (VPP) and a sustained fronto-central negativity (300-500 ms). Our results indicate that, like faces, bodies are processed configurally, and that within each category qualitative differences are observed for emotional as opposed to neutral images.

Does the human visual system contain perceptual mechanisms specialized for particular object categories such as faces? This question lies at the heart of a long-running debate in face perception. The face-specific hypothesis posits that face perception relies on mechanisms dedicated to faces, while the expertise hypothesis proposes that faces are processed by more generic mechanisms that operate on objects we have extended experience with. Previous studies that have addressed this question using acquired prosopagnosia are inconclusive because the non-face categories tested (e.g., cars) were not well-matched to faces in terms of visual exposure and perceptual experience. Here we compare perception of faces and bodies in four acquired prosopagnosics. Critically, we used face and body tasks that generate comparable inversion effects in controls, which indicates that our tasks engage orientation-specific perceptual mechanisms for faces and bodies to a similar extent. Three prosopagnosics were able to discriminate bodies normally despite their impairment in face perception. Moreover, they exhibited normal inversion effects for bodies, suggesting their body perception was carried out by the same mechanisms used by controls. Our findings indicate that the human visual system contains processes specialized for faces. (C) 2013 Elsevier B.V. All rights reserved.

Abstract Are faces recognized using more holistic representations than other types of stimuli? Taking holistic representation to mean representation without an internal part structure, we interpret the available evidence on this issue and then design new empirical tests. Based on previous research, we reasoned that if a portion of an object corresponds to an explicitly represented part in a hierarchical visual representation, then when that portion is presented in isolation it will be identified relatively more easily than if it did not have the status of an explicitly represented part. The hypothesis that face recognition is holistic therefore predicts that a part of a face will be disproportionately more easily recognized in the whole face than as an isolated part, relative to recognition of the parts and wholes of other kinds of stimuli. This prediction was borne out in three experiments: subjects were more accurate at identifying the parts of faces, presented in the whole object, than they were at identifying the same part presented in isolation, even though both parts and wholes were tested in a forced-choice format and the whole faces differed only by one part. In contrast, three other types of stimuli--scrambled faces, inverted faces, and houses--did not show this advantage for part identification in whole object recognition.

The body inversion effect is the finding that inverted body posture pictures are more difficult to recognize than upright body posture pictures are. The present study reinvestigated the body inversion effect in human observers using behavioral and eye movement measures to explore whether the body inversion effect correlates with specific eye movement features. Results showed that body postures elicited a robust and stable body inversion effect in reaction time throughout the experimental sessions. Eye-tracking data showed that the body inversion effect was robust only in the first fixation duration, but not in the second fixation duration. The analysis of the regions of interest showed that most fixations were located in the upper body for both the upright and the inverted body postures. Compared with inverted body postures, the upright postures led to a shorter reaction time and a shorter first fixation duration, but a larger portion of time to fixate on the head region, suggesting that participants tended to use head as a reference point to process upright body postures. For both the behavioral and the eye movement measures, the body inversion effect was robust for biomechanically possible body postures. However, for biomechanically impossible body postures (with angular manipulation of two joints), the effect was mixed. Although the error rate failed to show the body inversion effect, the reaction time measure and most eye movement measures, however, showed a body inversion effect. Overall, these results suggested that upright body postures are processed in expertise recognition and are processed configurally by human observers.

Abstract Previous behavioral and electrophysiological studies examining the body inversion effect, where inversion of a body stimulus reduces its recognition, suggested that information regarding human bodies is processed configurally. However, few studies to date have examined how the magnitude of the body inversion effect may be impacted by varying degrees of configural information present in a stimulus of interest. In the current study, upright and inverted body stimuli were presented across three body posture conditions, the whole body, piecemeal body (without head and trunk), and random body posture conditions, while response times, error rates, and event-related potentials were recorded. Behavioral measures and assessment of the N170 component, particularly at occipital-temporal site, revealed a robust difference between upright and inverted postures for both the whole body and piecemeal body posture conditions, which was not observed in the random body posture condition. The behavioral measure showed less errors and faster reaction times for upright compared with inverted orientation; however, the N170 component only showed typical effect of orientation (more negative and more delayed peak in waveform for the inverted compared with upright orientation) in the left hemisphere. The magnitude and direction of these differences were comparable for whole body and piecemeal postures. Overall, these results were consistent with the notion that it is the first-order information of body posture rather than the presence of the head (and trunk) that determines the body inversion effect.

This study examined the contributions of two previously identified brain regions he extrastriate and fusiform body areas (EBA and FBA)o the visual representation of the human form. Specifically we measured in these two areas the magnitude of fMRI response as a function of the amount of the human figure that is visible in the image, in the range from a single finger to the entire body. A second experiment determined the selectivity of these regions for body and body part stimuli relative to closely matched control images. We found a gradual increase in the selectivity of the EBA as a function of the amount of body shown. In contrast, the FBA shows a steplike function, with no significant selectivity for individual fingers or hands. In a third experiment we demonstrate that the response pattern seen in EBA does not extend to adjacent motion-selective human midtemporal area. We propose an interpretation of these results by analogy to nearby face-selective regions occipital face area (OFA) and fusiform face area (FFA). Specifically, we hypothesize that the EBA analyzes bodies at the level of parts (as has been proposed for faces in the OFA), whereas FBA (by analogy to FFA) may have a role in processing the configuration of body parts into wholes.

Visual recognition of human bodies is more difficult for upside down than upright presentations. This body inversion effect implies that body perception relies on configural rather than local processing. Although neuroimaging studies indicate that the visual processing of human bodies engages a large fronto-temporo-parietal network, information about the neural underpinnings of configural body processing is meager. Here, we used repetitive transcranial magnetic stimulation (rTMS) to study the causal role of premotor, visual, and parietal areas in configural processing of human bodies. Eighteen participants performed a delayed matching-to-sample task with upright or inverted static body postures. Event-related, dual-pulse rTMS was applied 150 ms after the sample stimulus onset, over left ventral premotor cortex (vPMc), right extrastriate body area (EBA), and right superior parietal lobe (SPL) and, as a control site, over the right primary visual cortex (V1). Interfering stimulation of vPMc significantly reduced accuracy of matching judgments for upright bodies. In contrast, EBA rTMS significantly reduced accuracy for inverted but not for upright bodies. Furthermore, a significant body inversion effect was observed after interfering stimulation of EBA and V1 but not of vPMc and SPL. These results demonstrate an active contribution of the fronto-parietal mirror network to configural processing of bodies and suggest a novel, embodied aspect of visual perception. In contrast, the local processing of the body, possibly based on the form of individual body parts instead of on the whole body unit, appears to depend on EBA. Therefore, we propose two distinct cortical routes for the visual processing of human bodies.

Patients with anorexia nervosa (AN) suffer from severe disturbances of body perception. It is unclear, however, whether such disturbances are linked to specific alterations in the processing of body configurations with respect to the local processing of body part details. Here, we compared a consecutive sample of 12 AN patients with a group of 12 age-, gender- and education-matched controls using an inversion effect paradigm requiring the visual discrimination of upright and inverted pictures of whole bodies, faces and objects. The AN patients presented selective deficits in the discrimination of upright body stimuli, which requires configural processing. Conversely, patients and controls showed comparable abilities in the discrimination of inverted bodies, which involves only detail-based processing, and in the discrimination of both upright and inverted faces and objects. Importantly, the body inversion effect negatively correlated with the persistence scores at the Temperament and Character Inventory, which evaluates increased tendency to convert a signal of punishment into a signal of reinforcement. These results suggest that the deficits of configural processing in AN patients may be associated with their obsessive worries about body appearance and to the excessive attention to details that characterizes their general perceptual style.

The perception of socially relevant stimuli (e.g., faces and bodies) has received considerable attention in the vision science community. It is now widely accepted that human faces are processed holistically and not only analytically. One observation that has been taken as evidence for holistic face processing is the face composite effect: Two identical top halves of a face tend to be perceived as being different when combined with different bottom halves. This supports the hypothesis that face processing proceeds holistically. Indeed, the interference effect disappears when the two face parts are misaligned (blocking holistic perception). In the present study, we investigated whether there is also a composite effect for the perception of body postures: Are two identical body halves perceived as being in different poses when the irrelevant body halves differ from each other? Both a horizontal (i.e., top-bottom body halves; Experiment 1) and a vertical composite effect (i.e., left-right body halves; Experiment 2) were examined by means of a delayed matching-to-sample task. Results of both experiments indicate the existence of a body posture composite effect. This provides evidence for the hypothesis that body postures, as faces, are processed holistically.

ABSTRACT Compared memory for faces with memory for other classes of familar and complex objects which, like faces, are also customarily seen only in 1 orientation (mono-oriented). Performance of 4 students was tested when the inspection and test series were presented in the same orientation, either both upright or both inverted, or when the 2 series were presented in opposite orientations. The results show that while all mono-oriented objects tend to be more difficult to remember when upside-down, faces are disproportionately affected. These findings suggest that the difficulty in looking at upside-down faces involves 2 factors: a general factor of familiarity with mono-oriented objects, and a special factor related only to faces. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

It has been recently argued that bodies are processed by a specialized processing mechanism. Central evidence was that body inversion reduces recognition abilities (body inversion effect; ) as much as it does for faces, but more than for other objects. Here we showed that the is markedly reduced for headless bodies and examined the reason for this unexpected finding. Two alternative hypotheses were examined. Either the is reduced for any type of incomplete body, or the head plays a special role in discrimination of body posture. Results show that omission of other body parts (leg or arms) did not influence the magnitude of the relative to complete bodies. Analogous manipulations with faces did not influence the magnitude of the face inversion effect. Importantly, similar to effects we found for headless bodies, discrimination abilities for upright bodies and the were markedly reduced for complete bodies that did not differ in head posture. We conclude that intact discrimination of body posture relies heavily on the head position. Our findings also imply that the and the face inversion effect may be generated by different mechanisms.