Denise Soria Bauser

Reduced connectivity between the left fusiform body area and the extrastriate body area in anorexia nervosa is associated with body image distortion

The aim of the present study was to investigate the network and its effective connectivity subserving body processing in women suffering from anorexia nervosa (AN) and also in healthy controls. Ten women diagnosed with AN and 15 healthy, age matched controls were investigated using fMRI during viewing images of bodies and chairs. Effective connectivity between cortical areas which are involved in human visual body processing was accessed. Effective connectivity analysis yielded evidence for a different network in AN and healthy controls during visual processing of human bodies. Left sided effective connectivity in the occipital cortex of women with AN showed a highly negative correlation with body size misjudgment. Present results yield evidence for altered networks for body processing in women with AN. Results explain body size misjudgment, a key feature in AN, which seems to be based on reduced effective connectivity in the body processing network.

Differences between perception of human faces and body shapes: Evidence from the composite illusion

The present study aimed to investigate whether human body forms--like human faces--undergo holistic processing. Evidence for holistic face processing comes from the face composite effect: two identical top halves of a face are perceived as being different if they are presented with different bottom parts. This effect disappears if both bottom halves are shifted laterally (misaligned) or if the stimulus is rotated by 180°. We investigated whether comparable composite effects are observed for human faces and human body forms. Matching of upright faces was more accurate and faster for misaligned compared to aligned presentations. By contrast, there were no processing differences between aligned and misaligned bodies. An inversion effect emerged, with better recognition performance for upright compared to inverted bodies but not faces. The present findings provide evidence for the assumption that holistic processing--investigated with the composite illusion--is not involved in the perception of human body forms.

Face and body perception in schizophrenia: a configural processing deficit?

Face and body perception rely on common processing mechanisms and activate similar but not identical brain networks. Patients with schizophrenia show impaired face perception, and the present study addressed for the first time body perception in this group. Seventeen patients diagnosed with schizophrenia or schizoaffective disorder were compared to 17 healthy controls on standardized tests assessing basic face perception skills (identity discrimination, memory for faces, recognition of facial affect). A matching-to-sample task including emotional and neutral faces, bodies and cars either in an upright or in an inverted position was administered to assess potential category-specific performance deficits and impairments of configural processing. Relative to healthy controls, schizophrenia patients showed poorer performance on the tasks assessing face perception skills. In the matching-to-sample task, they also responded more slowly and less accurately than controls, regardless of the stimulus category. Accuracy analysis showed significant inversion effects for faces and bodies across groups, reflecting configural processing mechanisms; however reaction time analysis indicated evidence of reduced inversion effects regardless of category in schizophrenia patients. The magnitude of the inversion effects was not related to clinical symptoms. Overall, the data point towards reduced configural processing, not only for faces but also for bodies and cars in individuals with schizophrenia.

BESST (Bochum Emotional Stimulus Set)—A pilot validation study of a stimulus set containing emotional bodies and faces from frontal and averted views

This article introduces the freely available Bochum Emotional Stimulus Set (BESST), which contains pictures of bodies and faces depicting either a neutral expression or one of the six basic emotions (happiness, sadness, fear, anger, disgust, and surprise), presented from two different perspectives (0° frontal view vs. camera averted by 45° to the left). The set comprises 565 frontal view and 564 averted view pictures of real-life bodies with masked facial expressions and 560 frontal and 560 averted view faces which were synthetically created using the FaceGen 3.5 Modeller. All stimuli were validated in terms of categorization accuracy and the perceived naturalness of the expression. Additionally, each facial stimulus was morphed into three age versions (20/40/60 years). The results show high recognition of the intended facial expressions, even under speeded forced-choice conditions, as corresponds to common experimental settings. The average naturalness ratings for the stimuli range between medium and high.

Behavioral and electrophysiological correlates of intact and scrambled body perception.

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.

Turn to me: electrophysiological correlates of frontal vs. averted view face and body processing are associated with trait empathy.

The processing of emotional faces and bodies has been associated with brain regions related to empathic responding in interpersonal contexts. The aim of the present Electroencephalography (EEG) study was to investigate differences in the time course underlying the processing of bodies and faces showing neutral, happy, or angry expressions. The P100 and N170 were analyzed in response to the presentation of bodies and faces. Stimuli were presented either from a perspective facing the observer directly or being averted by 45° to manipulate the degree to which the participants had the impression of being involved in a dyadic interpersonal interaction. Participants were instructed to identify the emotional expression (neutral, happy, or angry) by pressing the corresponding button. The result pattern mirrored poorer behavioral performance for averted relative to frontal stimuli. P100 amplitudes were enhanced and latencies shorter for averted relative to frontal bodies, while P100 and N170 components were additionally affected by electrode position and hemisphere for faces. Affective trait empathy correlated with faster recognition of facial emotions and most consistently with higher recognition accuracy and larger N170 amplitudes for angry expressions, while cognitive trait empathy was mostly linked to shorter P100 latencies for averted expressions. The results highlight the contribution of trait empathy to fast and accurate identification of emotional faces and emotional actions conveyed by bodies.

Eyeblink conditional discrimination learning in healthy young men is impaired after stress exposure.

Stress is known to influence the hippocampus. Eyeblink conditional discrimination learning is dependent on the hippocampus, but the effects of stress on the task are unknown. Male participants were allocated to a psychosocial stress condition (Trier Social Stress Test) or a control condition. Afterwards, a conditional discrimination task was performed. A tone (the CS) predicted an airpuff (the US) only when preceded by a specific visual stimulus (a red or a green colored square, the S+ and S-). Stressed participants showed a rise in cortisol and an increase in negative affect. Stressed participants also failed to acquire the conditional discrimination. They responded to all of the presented CS irrespective of the preceding occasion setter (S+ or S-). Controls, in contrast, acquired the discrimination rapidly. The present study provides further evidence for an impairing effect of acute stress on tasks relying on the hippocampal formation.

Is the whole the sum of its parts? Configural processing of headless bodies in the right fusiform gyrus

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 role of the head in configural body processing: Behavioural and electrophysiological evidence from the inversion and scrambling effect

The present study aimed to further explore the role of the head for configural body processing by comparing complete bodies with headless bodies and faceless heads (Experiment 1). A second aim was to further explore the role of the eye region in configural face processing (Experiment 2). Due to that, we conducted a second experiment with complete faces, eyeless faces, and eyes. In addition, we used two effects to manipulate configural processing: the effect of stimulus inversion and scrambling. The current data clearly show an inversion effect for intact bodies presented with head and faces including the eye region. Thus, the head and the eye region seem to be central for configural processes that are manipulated by the effect of stimulus inversion. Furthermore, the behavioural and electrophysiological body inversion effect depends on the intact configuration of bodies and is associated with the N170 as the face inversion effect depends on the intact face configuration. Hence, configural body processing depends not only on the presence of the head but rather on a complete representation of human bodies that includes the body and the head. Furthermore, configural face processing relies on intact and complete face representations that include faces and eyes.