Bigna Lenggenhager

Bodily sensation mapping (BSM) is a recently developed self-report tool for the assessment of emotions in which people draw their sensations of activation in a body silhouette. Following the circumplex model of affect, activity and valence are the underling dimensions of every emotional experience. The aim of this study was to introduce the neglected valence dimension in BSM. We found that participants systematically report valence-related sensations of bodily lightness for positive emotions (happiness, love, pride), and sensations of bodily heaviness in response to negative emotions (e.g., anger, fear, sadness, depression) with specific body topography (Experiment 1). Further experiments showed that both computers (using a machine learning approach) and humans recognize emotions better when classification is based on the combined activity- and valence-related BSMs compared to either type of BSM alone (Experiments 2 and 3), suggesting that both types of bodily sensations reflect dis...

The sense of a bodily self is thought to depend on adaptive weighting and integration of bodily afferents and prior beliefs. While the physical body changes in shape, size, and functionality across the lifespan, the sense of body ownership remains relatively stable. Yet, little is known about how multimodal integration underlying such sense of ownership is altered in ontogenetic periods of substantial physical changes. We aimed to study this link for the motor and the tactile domain in a mixed-realty paradigm where participants ranging from 7 to 80 years old saw their own body with temporally mismatching multimodal signals. Participants were either stroked on their hand or moved it, while they saw it in multiple trials with different visual delays. For each trial, they judged the visuo-motor/tactile synchrony and rated the sense of ownership for the seen hand. Visual dependence and proprioceptive acuity were additionally assessed. The results show that across the lifespan body ownership decreases with increasing temporal multisensory mismatch, both in the tactile and the motor domain. We found an increased sense of ownership with increasing age independent of delay and modality. Delay sensitivity during multisensory conflicts was not consistently related to age. No effects of age were found on visual dependence or proprioceptive accuracy. The results are at least partly in line with an enhanced weighting of top-down and a reduced weighting of bottom-up signals for the momentary sense of bodily self with increasing age.

Understanding the neural substrate of altered conscious states is an important cultural, scientific, and clinical endeavour. Although hypnosis causes strong shifts in conscious perception and cognition, it remains largely unclear how hypnosis affects information processing in cortical networks. Here we manipulated the depth of hypnotic states to study information processing between cortical regions involved in attention and awareness. We used high-density Electroencephalography (EEG) to record resting-state cortical activity from 30 hypnosis experts during two hypnotic states with different depth. Each participant entered a light and a deep hypnotic state as well as two well-matched control states. Bridging top-down and lateralisation models of hypnosis, we found that interhemispheric frontoparietal connectivity distinguished hypnosis and control conditions, while no dif- ference was found between the two hypnotic states. Using a graph-theoretic measure, we revealed that the amount of information passing through individual nodes (measured via betweenness centrality) is reduced during hypnosis relative to control states. Finally, we found that theta power was enhanced during hypnosis. Our result contributes to the current discussion around a role for theta power in bringing about hypnotic states, as well as other altered conscious states. Overall, our findings support the notion that altered top- down control in frontoparietal regions facilitates hypnosis by integrating information be- tween cortical hemispheres.

Depersonalisation (DP) is characterized by fundamental alterations to the sense of self that include feelings of detachment and estrangement from one's body. We conducted an online study in healthy participants (n = 514) with DP traits to investigate and quantify the subjective experience of body and self during waking and dreaming, as the vast majority of previous studies focussed on waking experience only. Investigating dreams in people experiencing DP symptoms may help us understand whether the dream state is a 'spared space' where people can temporarily 'retrieve' their sense of self and sense of bodily presence. We found that higher DP traits-i.e. higher scores on the Cambridge Depersonalisation Scale (CDS)-were associated with more frequent dream experiences from an outside observer perspective (r = 0.28) and more frequent dream experiences of distinct bodily sensations (r = 0.23). We also found that people with higher CDS scores had more frequent dream experiences of altered bodily perception (r = 0.24), more frequent nightmares (r = 0.33) and higher dream recall (r = 0.17). CDS scores were negatively correlated with body boundary scores (r = − 0.31) in waking states and there was a negative association between CDS scores and the degree of trust in interoceptive signals (r = − 0.52). Our study elucidates the complex phenomenology of DP in relation to bodily selfhood during waking and dreaming and suggests avenues for potential therapeutic interventions in people with chronic depersonalisation (depersonalisation-derealisation disorder). Transient depersonalisation (DP) experiences, which include fundamental alterations in the experience of one's bodily self 1-3 , are relatively common in the general population, with a lifetime prevalence rate of 26-74% 4. People who experience DP describe feeling detached or estranged from their body and self, and sometimes also their surroundings (derealisation) 5-8. People with persistent depersonalisation experiences are diagnosed with Depersonalisation disorder (DPD), a disturbing psychiatric condition estimated to be present in 1-2% of the population 9 , although it is thought to be under-diagnosed 10. The study reported here investigated the nonclinical experience of depersonalisation symptoms and their association with aspects of bodily selfhood during waking and dreaming. Scientists and philosophers distinguish different levels or aspects of self, and have generated a plethora of terms and definitions (see 11 for a review). 'Higher' levels of self include the narrative self and autobiographical self which require language and memory and the experience of a temporally extended existence. These are sometimes contrasted with a 'lower' bodily self: the experience of having/being a body. The most basic level of self-the minimal self-has been defined as the experience of being the subject of conscious experience (e.g., 12). Another proposal is that minimal phenomenal selfhood involves body ownership, self-identification, and selflocation 13. Drawing on Merleau-Ponty 14 and William James 15 , many scientists and philosophers now argue that the basic foundation of self, which grounds all layers of self, is anchored in the body 16,17. Supporting this, there

Highlights People with body integrity dysphoria (BID) desire the removal of the affected leg Ownership and agency are lower for the affected leg than the unaffected one Moral behavior is similar for BID and controls and the affected and unaffected leg Communicating self-gain lies with the affected leg further decreases ownership

There is a constant reciprocal flow of information between the malleable sensorimotor states of the body and cognitive functions, and some embodied cognition approaches argue that many cognitive-affective mechanisms depend on the physical characteristics of the body. To examine such influences of bodily state, the current study compared patients with body integrity dysphoria (BID) with an amputation desire of the lower limb to a healthy control group on an Implicit Association Test for self-identity and self-esteem, and a pain evaluation task. Patients with BID completed the tasks once while emulating their desired bodily state and once while simulating their undesired bodily state, while healthy controls were split into two groups: one control group completed the experiment once while either sitting on one leg and once while sitting in a normal position, whereas the other control group completed both experiments while sitting in a normal position. Results demonstrate that patients with BID implicitly identify more strongly with an amputated body, whereas healthy controls demonstrate stronger identification with a complete body, independent of bodily state. Furthermore, implicit self-esteem did not differ between the groups and was also not modulated by bodily state manipulation in any of the groups. Pain evaluation ratings were not influenced by bodily state manipulation, perspective, or consistency. Pain forced choice response times, however, revealed that individuals with BID were faster to judge whether the stimulus depicted was painful when simulating their desired bodily state. These results provide insightful information to how both the subjective sense of body, as well as more transient alterations of objective sensorimotor states of the physical body may exert selective pressure on certain cognitive tasks.

The visuo-spatial aspects of dreams and their relationship with the perception of other characters in dreams remain largely uncharted. • We examined the perspective (first-person perspective, 1PP or third-person perspective, 3PP), viewing angle on and distance to other dream bodies. • We examined the correlation between these visuo-spatial aspects and participants’ dream sensations related to different sensory modality experiences. • The results showed that 1PP is significantly more frequently adopted than 3PP in dreams. • We showed a significant predictive relationship between close distance intervals (0–90 cm and 90–180 cm) and the intensity of the total sensory experience which suggests that the stronger the sensory experience in dreams, the more closely other dream bodies felt from our own dream body.

An increasing amount of recent research has focused on the multisensory and neural bases of the bodily self. This pre-reflective form of self is considered as multifaceted, incorporating phenomenal components, such as self location, body ownership, first-person perspective, agency, and the perceptual body image. Direct electrical brain stimulation (EBS) during presurgical evaluation of epilepsy and brain tumor resection is a unique method to causally relate specific brain areas to the various phenomenal components of the bodily self. We conducted a systematic review of the literature describing altered phenomenal experience of the bodily self evoked by EBS. We included 42 articles and analyzed self reports from 221 patients. Three-dimensional density maps of EBS revealed that stimulation in the middle cingulum, inferior parietal lobule, supplementary motor area, posterior insula, hippocampal complex/amygdala, and precuneus most consistently altered one or several components of the bodily self. In addition, we found that only EBS in the parietal cortex induced disturbances of all five components of the bodily self considered in this review article. These findings inform current neuroscientific models of the bodily self.

Interoception, the perception of internal bodily signals, is fundamental to our sense of self. Even though theoretical accounts suggest an important role for interoception in the development of the self, empirical investigations are limited, particularly in infancy. Previous studies used preferential-looking paradigms to assess the detection of sensorimotor and multisensory contingencies in infancy, usually related to proprioception and touch. So far, only one recent study reported that infants discriminated between audiovisual stimuli presented synchronously or asynchronously with their heartbeat. This discrimination was related to the amplitude of the infant’s heartbeat evoked potentials (HEP), a neural correlate of interoception. In the current study, we measured looking preferences between synchronous and asynchronous visuocardiac (bimodal), and audiovisuocardiac (trimodal) stimuli as well as the HEP in conditions of different emotional contexts and with different degrees of sel...

Interoception, the perception of internal bodily signals, is fundamental to our sense of self. Even though theoretical accounts suggest an important role for interoception in the development of the self, empirical investigations are limited, particularly in infancy. Previous studies used preferential-looking paradigms to assess the de

The visuo-spatial aspects of dreams and their relationship with the perception of other characters in dreams remain largely uncharted.
•

We examined the perspective (first-person perspective, 1PP or third-person perspective, 3PP), viewing angle on and distance to other dream bodies.
•

We examined the correlation between these visuo-spatial aspects and participants’ dream sensations related to different sensory modality experiences.
•

The results showed that 1PP is significantly more frequently adopted than 3PP in dreams.
•

We showed a significant predictive relationship between close distance intervals (0–90 cm and 90–180 cm) and the intensity of the total sensory experience which suggests that the stronger the sensory experience in dreams, the more closely other dream bodies felt from our own dream body.

An increasing amount of recent research has focused on the multisensory and neural bases of the bodily self. This pre-reflective form of self is considered as multifaceted, incorporating phenomenal components, such as self location, body ownership, first-person perspective, agency, and the perceptual body image. Direct electrical brain stimulation (EBS) during presurgical evaluation of epilepsy and brain tumor resection is a unique method to causally relate specific brain areas to the various phenomenal components of the bodily self. We conducted a systematic review of the literature describing altered phenomenal experience of the bodily self evoked by EBS. We included 42 articles and analyzed self reports from 221 patients. Three-dimensional density maps of EBS revealed that stimulation in the middle cingulum, inferior parietal lobule, supplementary motor area, posterior insula, hippocampal complex/amygdala, and precuneus most consistently altered one or several components of the bodily self. In addition, we found that only EBS in the parietal cortex induced disturbances of all five components of the bodily self considered in this review article. These findings inform current neuroscientific models of the bodily self.

It is well established that vision, and in particular color, may modulate our experience of flavor. Such cross-modal correspondences have been argued to be bilateral, in the sense that one modality can modulate the other and vice versa. However, the amount of literature assessing how vision modulates flavor is remarkably larger than that directly assessing how flavor might modulate vision. This is more exaggerated in the context of cross-modal contrasts (when the expectancy in one modality contrasts the experience through another modality). Here, using an embodied mixed reality setup in which participants saw a liquid while ingesting a contrasting one, we assessed both how vision might modulate basic dimensions of flavor perception and how the flavor of the ingested liquid might alter the perceived color of the seen drink. We replicated findings showing the modulation of flavor perception by vision but found no evidence of flavor modulating color perception. These results are discus...

Acute and chronic states of physical pain are inherently linked to our bodily perception. Bodily illusion paradigms have demonstrated that an experimentally induced sense of body disownership can modulate both acute and chronic pain. Insight into the relationship between enduring clinical alterations in body perception and pain is much more limited. The current study examined both pain perception and placebo analgesia in Body Integrity Dysphoria (BID), a clinical model of long-term alterations of bodily disownership: in its most commonly studied variant, people feel like a part of their body does not belong to them, leading to a desire for amputation of a physically healthy limb. Heat stimulations were applied before and after a placebo intervention (sham analgesic cream) to the desired and the undesired leg of 19 patients with BID with a unilateral leg amputation desire. Pain perception was assessed using pain thresholds, and ratings for pain intensity and pain unpleasantness. Results show that pain perception and placebo efficacy were lower for the undesired than for the desired leg, demonstrating a potential link between a clinical disorder of body ownership, pain perception, and placebo analgesia.

"Body integrity dysphoria" (BID) is a severe condition affecting nonpsychotic individuals. In the amputation variant of BID, a limb may be experienced as not being part of the body, despite normal anatomical development and intact sensorimotor functions. We previously demonstrated altered brain structural (gray matter) and functional connectivity in 16 men with BID with a long-lasting and exclusive desire for left leg amputation. Here, we aimed to identify, in the same sample, altered patterns of white matter structural connectivity. Fractional anisotropy (FA), derived from diffusion tensor imaging data, was considered as a measure of structural connectivity. Results showed reduced structural connectivity of: (i) the right superior parietal lobule (rSPL) with the right cuneus, with the superior occipital and with the posterior cingulate gyri, (ii) the pars orbitalis of the right middle frontal gyrus (rMFGOrb) with the putamen, and (iii) the left middle temporal gyrus (lMTG) with the pars triangularis of the left inferior frontal gyrus. Increased connectivity was found between the right paracentral lobule (rPLC) and the right caudate nucleus. By using a complementary method of investigation, we confirmed and extended previous results from the same sample of individuals with BID, showing structural alterations between areas tuned to the processing of the sensorimotor representations of the affected leg (rPCL), and to higher-order components of bodily representation such as the body image (rSPL) and visual processing. Alongside this network for bodily awareness, other networks such as the limbic (rMFGOrb) and the mirror (lMTG) systems showed alterations in structural connectivity. These findings consolidate current understanding of the neural correlates of the amputation variant of BID, which might in turn guide diagnostics and rehabilitative treatments.

Purpose of review The experience of ourselves as an embodied agent with a first-person perspective is referred to as ‘bodily self’. We present a selective overview of relevant clinical and experimental studies. Recent findings Sharing multisensory body space with others can be observed in patients with structurally altered bodies (amputations, congenital absence of limbs), with altered functionality after hemiplegia, such as denial of limb ownership (somatoparaphrenia) and with alterations in bodily self-consciousness on the level of the entire body (e.g. in autoscopic phenomena). In healthy participants, the mechanisms underpinning body ownership and observer perspective are empirically investigated by multisensory stimulation paradigms to alter the bodily self. The resulting illusions have promoted the understanding of complex disturbances of the bodily self, such as out-of-body experiences. We discuss the role of interoception in differentiating between self and others and review...

Introduction: Neuroimaging of the self focused on high-level mechanisms such as language, memory or imagery of the self. Recent evidence suggests that low-level mechanisms of multisensory and sensorimotor integration may play a fundamental role in encoding self-location and the first-person perspective (Blanke and Metzinger, 2009). Neurological patients with out-of body experiences (OBE) suffer from abnormal self-location and the first-person perspective due to a damage in the temporo-parietal junction (Blanke et al., 2004). Although self-location and the first-person perspective can be studied experimentally (Lenggenhager et al., 2009), the neural underpinnings of self-location have yet to be investigated. To investigate the brain network involved in self-location and first-person perspective we used visuo-tactile multisensory conflict, magnetic resonance (MR)-compatible robotics, and fMRI in study 1, and lesion analysis in a sample of 9 patients with OBE due to focal brain damage ...

Limb apparent motion perception (LAMP) refers to the illusory visual perception of a moving limb upon observing two rapidly alternating photographs depicting the same limb in two different postures. Fast stimulus onset asynchronies (SOAs) induce the more visually guided perception of physically impossible movements. Slow SOAs induce the perception of physically possible movements. According to the motor theory of LAMP, the latter perception depends upon the observers’ sensorimotor representations. Here, we tested this theory in two independent studies by performing a central (study 1) and peripheral (study 2) manipulation of the body’s sensorimotor states during two LAMP tasks. In the first sham-controlled transcranial direct current stimulation between-subject designed study, we observed that the dampening of left sensorimotor cortex activity through cathodal stimulation biased LAMP towards the more visually guided perception of physically impossible movements for stimulus pairs at...

Patients suffering from body integrity dysphoria (BID) desire to become disabled, arising from a mismatch between the desired body and the physical body. We focus here on the most common variant, characterized by the desire for amputation of a healthy limb. In most reported cases, amputation of the rejected limb entirely alleviates the distress of the condition and engenders substantial improvement in quality of life. Since BID can lead to life-long suffering, it is essential to identify an effective form of treatment that causes the least amount of alteration to the person’s anatomical structure and functionality. Treatment methods involving medications, psychotherapy, and vestibular stimulation have proven largely ineffective. In this hypothesis article, we briefly discuss the characteristics, etiology, and current treatment options available for BID before highlighting the need for new, theory driven approaches. Drawing on recent findings relating to functional and structural bra...

Knowledge of the body is filtered by perceptual information, recalibrated through predominantly innate stored information, and neurally mediated by direct sensory motor information. Despite multiple sources, the immediate prediction, construction, and evaluation of one’s body are distorted. The origins of such distortions are unclear. In this review, we consider three possible sources of awareness that inform body distortion. First, the precision in the body metric may be based on the sight and positioning sense of a particular body segment. This view provides information on the dual nature of body representation, the reliability of a conscious body image, and implicit alterations in the metrics and positional correspondence of body parts. Second, body awareness may reflect an innate organizational experience of unity and continuity in the brain, with no strong isomorphism to body morphology. Third, body awareness may be based on efferent/afferent neural signals, suggesting that maj...

Conflicting multisensory signals may alter embodiment to produce self-identification with a foreign body, but the role of olfaction in this process has been overlooked. We studied in healthy participants how sex (male and female sweat odors) and gender (male and female cosmetic scents) olfactory stimuli contribute to embodiment. Participants saw, on a head mounted display, the first-person perspective of a sex mismatching person. Synchronous visuotactile stimulation was applied to enhance illusory embodiment. Simultaneously, they smelled either sex-or gender-congruent or incongruent stimuli. We assessed implicit (skin conductance responses to visual threats) and explicit (questionnaire) measures of embodiment. Stronger responses to threat were found when participants smelled the sex-congruent compared to the sex-incongruent odor, while no such differences were found for the cosmetic scents. According to the questionnaire, embodiment did not differ between conditions. Post-experimental assessment of the presented cues, suggest that while both sweat odors were considered generally male, cosmetic scents were not. The presented scents were generally not associated with the embodied body. Our results suggest that sex-related body odors influence implicit but not explicit aspects of embodiment and are in line with unique characteristics of olfaction in other aspects of cognition.

The loss of body ownership, the feeling that your body and its limbs no longer belong to you, presents a severe clinical condition that has proven difficult to study directly. We here propose a novel paradigm using mixed reality to interfere with natural embodiment using temporally conflicting sensory signals from the own hand. In Experiment 1 we investigated how such a mismatch affects phenomenological and physiological aspects of embodiment, and identified its most important dimensions using a principle component analysis. The results suggest that such a mismatch induces a strong reduction in embodiment accompanied by an increase in feelings of disownership and deafference, which was, however, not reflected in physiological changes. In Experiment 2 we refined the paradigm to measure perceptual thresholds for temporal mismatches and compared how different multimodal, mismatching information alters the sense of embodiment. The results showed that while visual delay decreased embodim...

Acute and chronic states of physical pain are inherently linked to our bodily perception. Bodily illusion paradigms have demonstrated that an experimentally induced sense of body disownership can modulate both acute and chronic pain. Insight into the relationship between enduring clinical alterations in body perception and pain is much more limited. The current study examined both pain perception and placebo analgesia in Body Integrity Dysphoria (BID), a clinical model of long-term alterations of bodily disownership: in its most commonly studied variant, people feel like a part of their body does not belong to them, leading to a desire for amputation of a physically healthy limb. Heat stimulations were applied before and after a placebo intervention (sham analgesic cream) to the desired and the undesired leg of 19 patients with BID with a unilateral leg amputation desire. Pain perception was assessed using pain thresholds, and ratings for pain intensity and pain unpleasantness. Results show that pain perception and placebo efficacy were lower for the undesired than for the desired leg, demonstrating a potential link between a clinical disorder of body ownership, pain perception, and placebo analgesia.

Bodily sensation mapping (BSM) is a recently developed self-report tool for the assessment of emotions in which people draw their sensations of activation in a body silhouette. Following the circumplex model of affect, activity and valence are the underling dimensions of every emotional experience. The aim of this study was to introduce the neglected valence dimension in BSM. We found that participants systematically report valence-related sensations of bodily lightness for positive emotions (happiness, love, pride), and sensations of bodily heaviness in response to negative emotions (e.g., anger, fear, sadness, depression) with specific body topography (Experiment 1). Further experiments showed that both computers (using a machine learning approach) and humans recognize emotions better when classification is based on the combined activity- and valence-related BSMs compared to either type of BSM alone (Experiments 2 and 3), suggesting that both types of bodily sensations reflect dis...

Bodily self-identification has shown to be easily altered through spatiotemporally congruent multimodal signals. While such manipulations are mostly studied through visuo-tactile or visuo-motor stimulation, here we investigated whether congruent visuo-olfactory cues might enhance illusory self-identification with an arbitrary object. Using virtual reality, healthy individuals saw a grapefruit from its supposed first-person perspective that was touched in synchrony with their own body. The touch attempted to replicate what was seen as softly squeezing the grapefruit. Crucially, when we additionally presented the smell of a grapefruit in synchrony with the squeezing, they self-identified stronger with the fruit than when they smelled strawberry.

Research has shown that conflicting multisensory signals may alter embodiment to the point of self-identifying with a foreign body, but the role of olfaction in this process has been overlooked. Here, we study in healthy participants how sex (male and female sweat odors) and gender (male and female cosmetic scents) olfactory stimuli contribute to embodiment. Participants saw from the perspective of a sex mismatching person in virtual reality and received synchronous visuo-tactile stimulation to elicit illusory embodiment of the seen body while smelling either sex- or gender-congruent stimuli. We assessed implicit (skin conductance responses to visual threats) and explicit (questionnaire) measures of embodiment. Stronger responses to threat were found when participants smelled the sex-congruent compared to the sex-incongruent odor, while no such differences were found for the cosmetic scents. According to the questionnaire, embodiment did not differ between conditions. Post-experimen...

Increased efforts in neuroscience try to understand mental disorders as brain disorders. In the present study we investigate how common a neuroreductionist inclination is in the popular mind. Identically graphed, simulated data of mind-brain correlations were shown in three contexts with presumably different presumptions about causality. 738 highly-educated laymen rated plausibility of causality attribution from brain to mind and from mind to brain for correlations between brain structural properties and mental phenomena in the context of commonly perceived brain-lesion induced behavior (aphasia), behavior-induced training effects (piano playing), and a newly described mental disorder (Body Integrity Dysphoria). The findings reveal the expected context-dependent modulation, but also a general tendency to more readily attribute causal inference from brain to mind than vice versa. We argue that this tendency has important consequences, especially in the context of Body Integrity Dysph...

Mounting evidence has demonstrated that embodied virtual reality, during which physical bodies are replaced with virtual surrogates, can strongly alter cognition and behavior even when the virtual body radically differs from one’s own. One particular emergent area of interest is the investigation of how virtual gender swaps can influence choice behaviors. Economic decision-making paradigms have repeatedly shown that women tend to display more prosocial sharing choices than men. To examine whether a virtual gender swap can alter gender-specific differences in prosociality, 48 men and 51 women embodied either a same- or different-gender avatar in immersive virtual reality. In a between-subjects design, we differentiated between specifically social and non-social decision-making by means of a virtually administered interpersonal and intertemporal discounting task, respectively. We hypothesized that a virtual gender swap would elicit social behaviors that stereotypically align with the ...

Introduction: Increased efforts in neuroscience try to understand mental disorders as brain disorders. In the present study, we investigate how common a neuroreductionist inclination is among highly educated people. In particular, we shed light on implicit presuppositions of mental disorders little is known about in the public, exemplified here by the case of body integrity dysphoria (BID) that is considered a mental disorder for the first time in ICD-11. Methods: Identically graphed, simulated data of mind-brain correlations were shown in 3 contexts with presumably different presumptions about causality. 738 highly educated lay people rated plausibility of causality attribution from the brain to mind and from mind to the brain for correlations between brain structural properties and mental phenomena. We contrasted participants’ plausibility ratings of causality in the contexts of commonly perceived brain lesion-induced behavior (aphasia), behavior-induced training effects (piano pl...

The phenomenon of sensory attenuation, that is, the perceptual reduction of intensity for self-generated stimuli, is considered a neurocognitive basis for self-other distinction. Corroboratory, such perceptual attenuation has been shown to be dependent on the sense of embodiment, that is, the perceptual incorporation of an object or body part into one’s body representation. In the present study, we tested whether this relationship is transferrable to unilateral upper limb amputees using a prosthesis. Thirteen participants were asked to touch their foot sole with a) their intact hand (self-touch), b) their prosthesis (prosthesis-touch), or c) let it be touched by another person (other-touch). Intensity of touch was assessed with a questionnaire. In addition, prosthesis embodiment was assessed by the recently introduced Prosthesis Embodiment Scale in nine participants. We found that both self-touch as well as prosthesis-touch was characterized by significant perceptual attenuation com...

The sense of a bodily self is thought to depend on adaptive weighting and integration of bodily afferents and prior beliefs. Evidence from studies using paradigms such as the rubber hand illusion and full body illusion suggests changes in the integration of visuotactile bodily signals throughout childhood. Here, we extended this line of research by assessing how bottom-up visuomotor synchrony and expectancy, modulated by visual appearance of virtual avatars, contribute to embodiment in children. We compared responses to a first-person perspective virtual full body illusion from 8-12-year-old children and adults, while manipulating synchrony of the avatar’s movements (synchronous, 0.5 s, 1 s delay compared to the participant’s movements), and appearance of the avatar (human or skeleton). We measured embodiment with both subjective questionnaires and objective skin conductance responses to virtual threat. Results showed that children experienced ownership for the virtual avatar in a s...