Neural underpinnings of body image and body schema disturbances

2021 ◽  
pp. 267-284
Author(s):  
Jasmine Ho ◽  
Bigna Lenggenhager

The sense of our body is fundamental to human self-consciousness. Many neurological and psychiatric disorders involve atypical corporeal awareness with symptomatology that might be very heterogeneous, affecting various aspects of the bodily self. A common dichotomy divides disorders of the bodily self into disorders affecting predominantly the body schema and disorders predominantly affecting the body image. Yet, increasing evidence suggests that body schema and body image are mutually dependent, making a clear categorization of most disorders difficult. This interdependence is illustrated with examples of a few selected disorders that encompass an atypical sense of the bodily self. A special focus is placed on underlying neural alterations in various body-related brain regions. While body schema-related disorders might rather be linked to a disruption in the integration of multisensory information into a coherent body representation, especially in premotor and posterior parietal areas, body image disturbances, particularly their affective and cognitive aspects, might be linked to a broader network centred around cortical midline structures that are crucially involved in self-referential processes.

Perception ◽  
10.1068/p5853 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1547-1554 ◽  
Author(s):  
Francesco Pavani ◽  
Massimiliano Zampini

When a hand (either real or fake) is stimulated in synchrony with our own hand concealed from view, the felt position of our own hand can be biased toward the location of the seen hand. This intriguing phenomenon relies on the brain's ability to detect statistical correlations in the multisensory inputs (ie visual, tactile, and proprioceptive), but it is also modulated by the pre-existing representation of one's own body. Nonetheless, researchers appear to have accepted the assumption that the size of the seen hand does not matter for this illusion to occur. Here we used a real-time video image of the participant's own hand to elicit the illusion, but we varied the hand size in the video image so that the seen hand was either reduced, veridical, or enlarged in comparison to the participant's own hand. The results showed that visible-hand size modulated the illusion, which was present for veridical and enlarged images of the hand, but absent when the visible hand was reduced. These findings indicate that very specific aspects of our own body image (ie hand size) can constrain the multisensory modulation of the body schema highlighted by the fake-hand illusion paradigm. In addition, they suggest an asymmetric tendency to acknowledge enlarged (but not reduced) images of body parts within our body representation.


2019 ◽  
Author(s):  
Stephen Gadsby

The distinction between body image and body schema has been incredibly influential in cognitive neuroscience. Recently, researchers have begun to speculate about the relationship between these representations (Gadsby, 2017; 2018; Pitron & de Vignemont, 2017; Pitron et al., 2018). Within this emerging literature, Pitron and colleagues (2018) proposed that the long-term body image and long-term body schema co-construct one another, through a process of reciprocal interaction. In proposing this model, they make two assumptions: that the long-term body image incorporates the spatial characteristics of tools, and that it is distorted in the case of Alice in wonderland syndrome. Here, I challenge these assumptions, with a closer examination of what the term “long-term body image” refers to. In doing so, I draw out some important taxonomic principles for research into body representation.


2020 ◽  
Author(s):  
Massieh Moayedi ◽  
Nasim Noroozbahari ◽  
Georgia Hadjis ◽  
Kristy Themelis ◽  
Tim V. Salomons ◽  
...  

AbstractHow we perceive our bodies is fundamental to our self-consciousness and our experience in the world. There are two types interrelated internal body representations—a subjective experience of the position of a limb in space (body schema) and the subjective experience of the shape and size of the limb (body image). Body schema has been extensively studied, but there is no evidence of the brain structure and network dynamics underpinning body image. Here, we provide the first evidence for the extrastriate body area (EBA), a multisensory brain area, as the structural and functional neural substrate for body shape and size. We performed a multisensory finger-stretch illusion that elongated the index finger. EBA volume and functional connectivity to the posterior parietal cortex are both related to the participants’ susceptibility to the illusion. Taken together, these data suggest that EBA structure and connectivity encode body representation and body perception disturbances.


Author(s):  
Minoru Asada

Proprioception is our ability to sense the position of our own limbs and other body parts in space, and body schema is a body representation that allows both biological and artificial agents to execute their actions based on proprioception. The proprioceptive information used by current artificial agents (robots) is mainly related to posture (and its change) and consists of joint angles (joint velocities) given a linked structure. However, the counterpart in biological agents (humans and other animals) includes more complicated components with associated controversies concerning the relationship between the body schema and the body image. A new trend of constructive approaches has been attacking this topic using computational models and robots. This chapter provides an overview of the biology of proprioception and body representation, summarizes the classical use of body schema in robotics, and describes a series of constructive approaches that address some of the mysteries of body representation.


2021 ◽  
Author(s):  
Janna M. Gottwald ◽  
Laura Bird ◽  
Andrew J. Bremner ◽  
Dorothy Cowie

Children’s and adults’ body representation is constrained by bottom-up multisensory information and by top-down knowledge on possible postures. Using the rubber hand illusion paradigm, this study (N = 229) investigates whether different fake hand sizes (60%, 80%, 100%, 120% or 140% of typical hand size) constrain embodiment in three age groups (6- to 7-year-olds, 12- to 13-year-olds, and adults). Embodiment was measured by questionnaire, proprioceptive drift, and affordance judgements. In line with previous work, we found robust effects of age and synchrony, with higher responses at younger ages and under conditions of visual-tactile synchrony. There were no significant effects of hand size on proprioceptive drift or self-rated hand ownership; nor did participants verbally report that their hand had changed size. Participants of all ages therefore embodied a differently-sized fake hand, without being explicitly aware of the size change. However, manual judgments of own-hand size were significantly influenced by the size of the previously seen fake hand. Therefore, participants did implicitly incorporate a size change into their body schema. In sum, embodiment of differently-sized hands reveals substantial plasticity in body representation, modulated strongly by multisensory information and age. Further, the embodiment of a differently-sized hand specifically affects action-oriented representations of the body.


1981 ◽  
Vol 26 (4) ◽  
pp. 224-227 ◽  
Author(s):  
David M. Garner

Despite much recent interest in the objective measurement of body image in anorexia nervosa, many questions remain regarding basic mechanisms responsible for the findings as well as their meaning in the disorder. It is unclear if “whole body” measures assess the same underlying phenomena as the “body part” method, and it is unclear if body image disturbances are etiologic or a byproduct of anorexia nervosa. The possible association between self-esteem and body satisfaction and the relationship of the latter variable to actual size estimation supports the hypothesis that size perception may be closely tied to satisfaction with non-physical aspects of self. Finally it must be determined if over estimation is a function of a general psychological disturbance or of a deficit of specific interest in this disorder. Despite these questions, the way in which anorexic patients see themselves as well as the cognitive and affective responses to this perception remains an interesting and potentially fruitful area of study with this disorder.


Body schema refers to the system of sensory-motor functions that enables control of the position of body parts in space, without conscious awareness of those parts. Body image refers to a conscious representation of the way the body appears—a set of conscious perceptions, affective attitudes, and beliefs pertaining to one’s own bodily image. In 2005, Shaun Gallagher published an influential book entitled ‘How the Body Shapes the Mind’. This book not only defined both body schema (BS) and body image (BI), but also explored the complicated relationship between the two. The book also established the idea that there is a double dissociation, whereby body schema and body image refer to two different, but closely related, systems. Given that many kinds of pathological cases can be described in terms of body schema and body image (phantom limbs, asomatognosia, apraxia, schizophrenia, anorexia, depersonalization, and body dysmorphic disorder, among others), we might expect to find a growing consensus about these concepts and the relevant neural activities connected to these systems. Instead, an examination of the scientific literature reveals continued ambiguity and disagreement. This volume brings together leading experts from the fields of philosophy, neuroscience, psychology, and psychiatry in a lively and productive dialogue. It explores fundamental questions about the relationship between body schema and body image, and addresses ongoing debates about the role of the brain and the role of social and cultural factors in our understanding of embodiment.


2021 ◽  
pp. 229-243
Author(s):  
Jonathan Cole

In neurological illnesses, the body may present itself to perception in ways which allows insights into the concepts of body image and body schema. Three such conditions are explored. From those who live with spinal cord injury, paralysed and insentient from the neck down, aspects of the importance of the body in one’s sense of self are revealed. Some also describe a coming to terms with their altered bodies. When considering the body image, its adaptability and this reconciliation to a new normal should be considered. Studies on acquired severe sensory loss explore how conscious control, at the body image level, may partially replace the deafferented body schema. There is little evidence, however, for these subjects extending access to previously non-conscious motor schema. Lastly, some narratives from those with congenital absence of movement of facial muscles describe reduced emotional experience and felt embodiment as children. These can be developed as young adults, through shared social interactions. The importance of the social in elaboration of the body image is further implicit in a consideration of the stigma associated with facial disfigurement. Others’ responses to one’s body are crucial in developing our body image and sense of self.


2021 ◽  
pp. 133-151 ◽  
Author(s):  
Noriaki Kanayama ◽  
Kentaro Hiromitsu

Is the body reducible to neural representation in the brain? There is some evidence that the brain contributes to the functioning of the body from neuroimaging, neurophysiological, and lesion studies. Well-known dyadic taxonomy of the body schema and the body image (hereafter BSBI) is based primarily on the evidence in brain-damaged patients. Although there is a growing consensus that the BSBI exists, there is little agreement on the dyadic taxonomy because it is not a concrete and common concept across various research fields. This chapter tries to investigate the body representation in the cortex and nervous system in terms of sensory modality and psychological function using two different approaches. The first approach is to review the neurological evidence and cortical area which is related to body representation, regardless of the BSBI, and then to reconsider how we postulate the BSBI in our brain. It can be considered that our body representation could be constructed by the whole of the neural system, including the cortex and peripheral nerves. The second approach is to revisit the BSBI conception from the viewpoint of recent neuropsychology and propose three types of body representation: body schema, body structural description, and body semantics. This triadic taxonomy is considered consistent with the cortical networks based on the evidence of bodily disorders due to brain lesions. These two approaches allow to reconsider the BSBI more carefully and deeply and to give us the possibility that the body representation could be underpinned with the network in the brain.


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