Biology subjects

de Gelder, B.

Publications and source records attributed to de Gelder, B..

At least 19 recordsLinked to original sources

bioRxiv2026

Local Motion Is Sufficient for Human Body Movement Perception in High-Level Visual Cortex

Perceiving the movements of other living organisms is a fundamental ability across species. Although several cortical regions are selective for static body features, it is unclear whether these areas also encode motion cues independently of body shapes. Here, we isolated optical flow patterns from naturalistic body movements using synthesized videos that eliminate explicit body shape information. Behavioral results suggest that participants successfully recognized walking directions from the shape-free flow motion stimuli. Using ultra-high field fMRI, we found that three body-motion-related areas, fusiform gyrus (FG), lateral occipitotemporal cortex (LOTC), and posterior superior temporal sulcus (pSTS), were sensitive to both the amount and the spatiotemporal structure of flow motion. Critically, the flow motion effects were significantly correlated to voxel-wise body motion selectivity in FG and LOTC, but not to body shape selectivity in any of the ROIs. These findings identify flow motion as a distinct and behaviorally sufficient cue for body perception, which could dissociate the neural mechanism underlying motion and shape encoding in FG and LOTC.

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bioRxiv2025

Natural body-selective motion processing in humans: Evidence from event-related potentials

As social species, perception of body motion is crucial to daily interactions, yet the underlying neural processes and their dynamics are not fully understood. While well-established EEG evidence has identified temporal markers of biological body motion, and recent fMRI research points to naturalistic body networks, the temporal markers of higher-level, naturalistic body motion processes remain unknown. The present study bridges this gap, showing that at the stage of P2, the cortex may already distinguish between the global motion of naturalistic bodies compared to objects. Exploratory analyses point to a similar body-specific modulation across stimulus species, namely human and monkey. The findings of the present study expand our understanding of body motion processes, in line with emerging, integrative models of multi-faceted body processes.

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bioRxiv2025

Neural encoding of biomechanically (im)possible human movements in occipitotemporal cortex

Understanding how the human brain processes body movements is essential for clarifying the mechanisms underlying social cognition and interaction. This study investigates the encoding of biomechanically possible and impossible body movements in occipitotemporal cortex using ultra-high field 7Tesla fMRI. By predicting the response of single voxels to impossible/possible movements using a computational modelling approach, our findings demonstrate that a combination of postural, biomechanical, and categorical features significantly predicts neural responses in the ventral visual cortex, particularly within the extrastriate body area (EBA), underscoring the brains sensitivity to biomechanical plausibility. Lastly, these findings highlight the functional heterogeneity of EBA, with specific regions (middle/superior occipital gyri) focusing on detailed biomechanical features and anterior regions (lateral occipital sulcus and inferior temporal gyrus) integrating more abstract, categorical information.

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bioRxiv2024

Behavioral and neural evidence for perceptual predictions in social interactions

The ability to predict others behavior is crucial for social interactions. The goal of the present study was to test whether predictions are derived during observation of social interactions and whether these predictions influence how the whole-body emotional expressions of the agents are perceived. Using a novel paradigm, we induced social predictions in participants by presenting them with a short video of a social interaction in which a person approached another person and greeted him by touching the shoulder in either a neutral or an aggressive fashion. The video was followed by a still image showing a later stage in the interaction and we measured participants behavioral and neural responses to the still image, which was either congruent or incongruent with the emotional valence of the touching. We varied the strength of the induced predictions by parametrically reducing the saliency of emotional cues in the video. Behaviorally, we found that reducing the emotional cues in the video led to a significant decrease in participants ability to correctly judge the appropriateness of the emotional reaction in the image. At the neural level, EEG recordings revealed that observing an angry reaction elicited significantly larger N170 amplitudes than observing a neutral reaction. This emotion effect was only found in the high prediction condition (where the context in the preceding video was intact and clear), not in the mid and low prediction conditions. We further found that incongruent conditions elicited larger N300 amplitudes than congruent conditions only for the neutral images. Our findings provide evidence that viewing the initial stages of social interactions triggers predictions about their outcome in early cortical processing stages.

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bioRxiv2024

Awareness is determined by emotion and gender

Traditionally, consciousness studies focus on domain general cognitive processes rather than on specific information reaching subjective awareness. The present study (N = 45) used visual masking and whole-body images to investigate whether the specific emotional expression as well as gender of the stimuli and of the participants impact awareness. Our results show that participants awareness responses reflect differences in the specific emotion of the stimuli, that these differences are a function of the gender of the stimuli as well as the gender of the participants and that minimal awareness may be associated with emotion specific features of the body images. Overall, we observed that threatening expressions are more easily detected than fearful ones, especially by males presented with male stimuli. Our findings underscore the importance of affective factors for theories of consciousness and underscore the significance of gender differences in emotional processing, often overlooked in past face and body emotion recognition studies.

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bioRxiv2024

Connectivity and functional diversity of different temporo-occipital nodes for action perception

The temporo-occipital cortex (TOC) plays a key role in body and action perception, but current understanding of its functions is still limited. TOC body regions are heterogeneous and their role in action perception is poorly understood. This study adopted data-driven approaches to region selectivity and investigated the connectivity of TOC nodes and the functional network sensitivity for different whole body action videos. In two human 7T fMRI experiments using independent component analysis, four adjacent body selective nodes were detected within the TOC network with distinct connectivity profiles and functional roles. Action type independent connectivity was observed for the posterior-ventral node to the visual cortex, the posterior-dorsal node to the precuneus and the anterior nodes to the frontal cortex. Action specific connectivity modulations were found in middle frontal gyrus for the aggressive condition with increased connectivity to the anterior node and decreased connectivity to the posterior-dorsal node. But for the defensive condition, node-nonspecific enhancement was found for the TOC-cingulate connectivity. By addressing the issue of multiple nodes in the temporo-occipital network we show a functional dissociation of different body selective centres related to the action type and a potential hierarchy within the TOC body network.

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bioRxiv2023

Theta activity discriminates high-level, species-specific body processes

Among social stimuli that trigger rapid reactions, body images occupy a prominent place. Given that bodies carry information about other agents intentions, actions and emotional expressions, a foundational question concerns the neural basis of body processing. Previous fMRI studies have investigated this but were not yet able to clarify the time course and its functional significance. The present EEG study investigated the role of slow oscillatory cortical activity in body processing and species-specificity. Human participants viewed naturalistic images of human and monkey bodies, faces, and objects, along with mosaic-scrambled versions to control for low-level visual features. Analysis of event-related theta power (4 - 7 Hz) combined with data-driven methods revealed a strong, body-evoked neural response that is specific to human bodies and likely originates from a widespread cortical region during a time window of 150 - 550 ms after the onset of the body image. Our results corroborate recent research proposing a widespread, species-specific cortical network of human body processing. We submit that this network may play an essential role in linking body processes to movement intentions.

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bioRxiv2023

Early threat perception is independent of later cognitive and behavioral control. A virtual reality-EEG-ECG study

Research on social threat has shown influences of various factors, such as agent characteristics, proximity and social interaction on social threat perception. An important, yet understudied aspect of threat experience concerns the ability to exert control over the thread. In this study, we used a Virtual Reality (VR) environment showing an approaching avatar that was either angry (threatening body expression) or neutral (neutral body expression) and informed participants to stop avatars from coming closer under five levels of control success (0, 25, 50, 75, or 100%) when they felt uncomfortable. Behavioral results revealed that social threat triggered faster reactions at a greater virtual distance from the participant than the neutral avatar. Event-related potentials (ERPs) revealed that the angry avatar elicited a larger N170/vertex positive potential (VPP) and a smaller N3 than the neutral avatar. The 100% control condition elicited a larger late positive potential (LPP) than the 75% control condition. In addition, we observed enhanced theta power and accelerated heart rate for the angry avatar vs. neutral avatar, suggesting that these measures index threat perception. Our results indicate that perception of social threat takes place in early to middle cortical processing stages, and control ability is associated with cognitive evaluation in middle to late stages.

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bioRxiv2022

Voxelwise encoding models of body stimuli reveal a representational gradient from low-level visual features to postural features in extrastriate body area.

Previous research has focused on the role of the extrastriate body area (EBA) in category-specific body representation, but the specific features that are represented in this area are not well understood. This study used ultra-high field fMRI and banded ridge regression to investigate the coding of body images by comparing the performance of three encoding models in predicting brain activity in ventral visual cortex and specifically the EBA. Our results suggest that EBA represents body stimuli based on a combination of low-level visual features and postural features. Author SummaryHistorically, research on body representation in the brain has focused on category-specific representation, using fMRI to investigate the most posterior body selective region, the extrastriate body area (EBA). However, the role of this area in body perception is still not well understood. This study aims to clarify the role of EBA, in coding information about body images. Using ultra-high field neuroimaging (fMRI) and advanced encoding techniques we tested different computational hypotheses to understand how body images are represented in EBA. Our results suggest that EBA represents bodies using a combination of low-level properties and postural information extracted from the stimulus.

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bioRxiv2022

Perceptual awareness is gradual in temporal and dichotomous in fronto-parietal cortices

Two major issues in consciousness research concern the measuring methods that determine perceptual unawareness and whether consciousness is a gradual or an all-or-nothing phenomenon. This 7T fMRI study addresses both questions using a continuous flash suppression paradigm with an emotional recognition task (fear vs neutral bodies) in combination with the perceptual awareness scale. Behaviorally, recognition sensitivity increased linearly with increased stimuli awareness and was at chance level during perceptual unawareness. Threat expressions triggered a slower heart rate than neutral ones during almost clear experience of the stimulus, indicating freezing behavior. The activity in occipital, temporal, parietal and frontal regions as well as in amygdala increased with increased stimulus awareness while the activity in early visual areas showed the opposite pattern. The relationship between temporal area activity and perceptual awareness was better characterized by a gradual model while the activity in fronto-parietal areas by a dichotomous model, suggesting different roles in conscious processing. Interestingly, no evidence of non-conscious processing was found in amygdala as well as no significant effect of emotion, in disagreement with the functions long ascribed to this subcortical structure.

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bioRxiv2022

Gradual relation between perceptual awareness, recognition and pupillary responses to social threat

There is substantial evidence about affective stimulus processing outside awareness in healthy participants and brain-damaged patients. However, there are still methodological concerns mainly relating to the methods used to assess awareness. In two experiments, we investigated the processing of social threat in healthy participants by combining the continuous flash suppression paradigm and the perceptual awareness scale, a finer measure of perceptual awareness than dichotomous (seen/unseen) responses. Our behavioral results show a gradual relationship between emotional recognition and perceptual awareness. Recognition sensitivity was also higher for fearful than angry bodies for all visual awareness levels except for the perceptual unawareness condition where performance was at chance level. Interestingly, angry body expressions were suppressed for a shorter duration than neutral and fearful ones. Pupil dilation was a function of affective expression, the duration of suppression and the level of perceptual awareness. In conclusion, behavioral as well as pupillary responses showed a gradual relationship with perceptual awareness, and this relationship was influenced by the specific stimulus category.

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bioRxiv2022

A large-scale brain network of species-specific dynamic human body perception

This ultrahigh field 7T fMRI study addressed the question of whether there exists a core network of brain areas at the service of different aspects of body perception. Participants viewed naturalistic videos of monkey and human faces, bodies, and objects along with mosaic-scrambled videos for control of low-level features. ICA-based network analysis was conducted to find body and species modulations at both the voxel and the network levels. Among the body areas, the highest species selectivity was found in the middle frontal gyrus and amygdala. Two large-scale networks were highly selective to bodies, dominated by the lateral occipital cortex and right superior temporal sulcus (STS) respectively. The right STS network showed high species selectivity, and its significant human body-induced node connectivity was focused around the extrastriate body area (EBA), STS, temporoparietal junction (TPJ), premotor cortex, and inferior frontal gyrus (IFG). The human body-specific network discovered here may serve as a brain-wide internal model of the human body serving as an entry point for a variety of processes relying on body descriptions as part of their more specific categorization, action, or expression recognition functions.

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bioRxiv2022

Brain morphometric changes in congenitally blind subjects: a 7 Tesla MRI study

We used ultra-high field (7 Tesla) magnetic resonance imaging (MRI) at submillimeter resolution to assess structural brain changes in congenitally blind (CB) compared to matched normal sighted control (SC) subject groups. Region-of-interest analysis revealed grey matter (GM) volumetric reductions in the CB group in left cuneus and occipital pole, right posterior collateral sulcus and right occipito-temporal medial lingual sulcus. Non-visual areas with GM reductions in CB included the left central, postcentral and superior frontal gyri, and the right subcallosal gyrus. In contrast, there were no significant group differences in cortical thickness when using stringent statistical criteria. Regional differences in white matter (WM) showed an overall pattern similar as that of GM changes, characterized by volume reductions in occipital, parietal and temporal areas, but with additional reductions in precuneus and medial orbitofrontal cortex. Differences in cortical curvature were mostly situated in the occipital cortex and bore a close relationship with areas showing GM alterations; they may be indicative of increased cortico-cortical connectivity of the visually-deprived occipital cortex. The CB group had GM reductions in the basal ganglia, i.e., caudate nucleus, putamen, nucleus accumbens, globus pallidus, and thalamus. Within the cerebellum, GM and WM volumes were also reduced in the CB. Segmentation of the thalamus, hippocampus and amygdala into anatomic divisions revealed GM reductions in a number of thalamic nuclei, a few hippocampal regions, but not within amygdala. There were no findings of increased volume or cortical thickness in the CB group. Together, these data reveal a multitude of GM and WM reductions in CB, comprising not only the occipital cortex, but also temporal, parietal, and prefrontal cortices, as well as the basal ganglia and cerebellum. These findings in the CB may seem at odds with the large literature showing that the visually-deprived occipital cortex becomes a multimodal cortex responding to diverse non-visual sensory and cognitive inputs. The seeming mismatch between morphological atrophy and enhanced multimodality of occipital areas combined with superior performance by the CB in various non-visual tasks poses a challenge for our understanding of brain plasticity.

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bioRxiv2021

Subjective understanding of actions and emotions involves the interplay of the semantic and action observation networks in the brain

Previous studies have investigated the neural basis of action and emotion perception conveyed by whole body postures and movements. However, subjective understanding of other peoples bodily actions and emotions, raises different issues that are currently not well understood and have so far seldom been investigated. In this 7T fMRI study, we proceeded beyond conventional univariate/multivariate analyses with predefined categories, and examined the representational geometry of subjective action- and emotion-understanding by mapping individual subjective reports with word embeddings. Dimensionality reduction revealed that the representations for perceived action and emotion were high dimensional, each correlated to but were not reducible to the predefined action and emotion categories. Searchlight representational similarity analysis showed that the representations in the left middle superior temporal sulcus and left dorsal premotor cortex corresponded to the subjective action and emotion understanding of the participants. Furthermore, using task-residual functional connectivity and hierarchical clustering, we found that areas in the action observation network and the semantic/default-mode network were functionally connected to these two seed regions, and showed similar representations. Our study provides direct evidence that both networks were concurrently involved in subjective action and emotion understanding. Our approach shows how subjective understanding of action and emotion stimuli can be reliably studied and complement insights based on from predefined stimulus categories.

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bioRxiv2020

Culture influences audiovisual emotion perception in early sensory areas

Emotion perception from facial and vocal expressions is a multisensory process critical for human social interaction. When asked to judge emotions by attending to either face or voice, the accuracy was higher when facial expressions are congruent with vocal expressions than when they are incongruent. This congruency effect was shown to be affected by cultural background. Here we conducted functional MRI alongside a multisensory emotion perception task involving Japanese and Dutch participants. They were presented with movies in which congruent or incongruent emotions were expressed through faces and voices. The participants were asked to judge the emotion of either the face or the voice. Consistent with previous studies, behavioral results showed an interaction between group and task. fMRI results revealed that during voice-based judgement, congruency effects of the primary visual cortex, by means of the task related activity of congruent stimuli subtracted by that of incongruent stimuli, were more prominent in the Dutch group than in Japanese group. Finally, behavioral and neural congruency effects of the primary visual cortex were positively correlated only in the Dutch group. Taken together, our results show that culture affects the activities of early sensory areas in multisensory perception from facial and vocal expressions.

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bioRxiv2020

The dynamics of body category and emotion processing in high-level visual, prefrontal and parietal cortex.

Recent studies provide an increasingly understanding of how visual objects categories like faces or bodies are represented in the brain but also raised the question whether a category based or more network inspired models are more powerful. Two important and so far sidestepped issues in this debate concern, first, how major category attributes like the emotional expression directly influence category representation and second, whether category and attribute representation are sensitive to task demands. This study investigated the impact of a crucial category attribute like emotional expression on category activity and whether this varies with the participants task. Using (fMRI) we measured BOLD responses while participants viewed whole body expressions and performed either an explicit (emotion) or an implicit (shape) recognition task. Our results based on multivariate methods show that the type of task is the strongest determinant of brain activity and can be decoded in EBA, VLPFC and IPL. Brain activity was higher for the explicit task condition in VLPFC and was not emotion specific. This pattern suggests that during explicit recognition of the body expression, body category representation may be strengthened, and emotion and action related activity suppressed. Taken together these results stress the importance of the task and of the role of category attributes for understanding the functional organization of high level visual cortex.

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bioRxiv2020

Limb contraction drives fear perception

Humans and other primate species are experts at recognizing affective information from body movements but the underlying brain mechanisms are still largely unknown. Previous research focusing on the brain representation of symbolic emotion categories has led to mixed results. This study used representational similarity and multi-voxel pattern analysis techniques to investigate how postural and kinematic features computed from affective whole-body movement videos are related to brain processes. We show that body posture and kinematics differentially activated brain regions indicating that this information might be selectively encoded in these regions. Most specifically, the feature limb contraction seemed to be particularly relevant for distinguishing fear and it was represented in several regions spanning affective, action observation and motor preparation networks. Our approach goes beyond traditional methods of mapping symbolic emotion categories to brain activation/deactivation by discovering which specific movement features are encoded in the brain, and possibly drive automatic emotion perception.

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bioRxiv2019

Decoding of emotion expression in the face, body and voice reveals sensory modality specific representations.

A central issue in affective science is whether the brain represents the emotional expressions of faces, bodies and voices as abstract categories in which auditory and visual information converge in higher order conceptual and amodal representations. This study explores an alternative theory based on the hypothesis that under naturalistic conditions where affective signals are acted upon that rather than reflected upon, major emotion signals (face, body, voice) have sensory specific brain representations. During fMRI recordings, participants were presented naturalistic dynamic stimuli of emotions expressed in videos of either the face or the whole body, or voice fragments. To focus on automatic emotion processing and bypass explicit emotion cognition relying on conceptual processes, participants performed an unrelated target detection task presented in a different modality than the stimulus. Using multivariate analysis to asses neural activity patterns in response to emotion expressions in the different stimuli types, we show a distributed brain organization of affective signals in which distinct emotion signals are closely tied to the sensory origin. Our findings are consistent with the notion that under ecological conditions the various sensory emotion expressions have different functional roles, even when from an abstract conceptual vantage point they all exemplify the same emotion category.

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