Aplasic phantoms and the mirror neuron system: An enactive, developmental perspective

Phantom limb experiences demonstrate an unexpected degree of fragility inherent in our self-perceptions. This is perhaps most extreme when congenitally absent limbs are experienced as phantoms. Aplasic phantoms highlight fundamental questions about the physiological bases of self-experience and the ontogeny of a physical, embodied sense of the self. Some of the most intriguing of these questions concern the role of mirror neurons in supporting the development of self–other mappings and hence the emergence of phantom experiences of congenitally absent limbs. In this paper, we will examine the hypothesis that aplasic phantom limb experience is the result of an ontogenetic interplay between body schemas and mirror neuron activity and that this interplay is founded on embedding in a social context. Phantom limb experience has been associated with the persistence of subjective experience of a part of the body after deafferentation through surgical or traumatic removal. We maintain that limited association is inconsistent with the extent to which phantom limb experience is reported by aplasic individuals.     

Normal body scheme and absent phantom limb experience in amputees while dreaming

While dreaming amputees often experience a normal body image and the phantom limb may not be present. However, dreaming experiences in amputees have mainly been collected by questionnaires. We analysed the dream reports of amputated patients with phantom limb collected after awakening from REM sleep during overnight videopolysomnography (VPSG). Six amputated patients underwent overnight VPSG study. Patients were awakened during REM sleep and asked to report their dreams. Three patients were able to deliver an account of a dream. In all dreaming recalls, patients reported that the amputated limbs were intact and completely functional and they no longer experienced phantom limb sensations. Phantom limb experiences, that during wake result from a conflict between a pre-existing body scheme and the sensory information on the missing limb, were suppressed during sleep in our patients in favour of the image of an intact body accessed during dream.     

Corporeal awareness and proprioceptive sense of the phantom

Phantom limb perception almost invariably follows limb amputation, and can be characterized by various corporeal and proprioceptive qualities. We report a study of 283 amputees, which administered a structured questionnaire to systematically determine the relative frequency and nature of various bodily aspects of phantom limb perception. These include the size, shape, posture, and telescoping of the phantom; exteroceptive sensations of itch, touch, pressure, vibration, temperature, and ‘electric’ sensations; and prosthesis embodiment. Phantom limbs were generally found to be characterized by properties that parallel those of the intact body, although with anatomically impossible configurations sometimes being perceived. We suggest that both the internal limb image and limb schemata play a significant role in the continued perception of phantom limbs.     

Supernumerary phantoms: a comment on Grossi, et al.'s (2002) spare thoughts on spare limbs

A recently published case report of a supernumerary phantom limb in a man with left-sided hemiplegia did not take note that this phenomenon has been extensively documented in the neurological literature for well over 100 years. The present comment provides a brief introduction to the clinical and experimental approaches to supernumerary phantom limbs. It also emphasizes the theoretical importance of this condition for understanding the neurological mechanisms subserving the experience of having a body.     

The Impact of Phantom Decoys on Choices and Perceptions

Phantoms are dominating, attractive alternatives that are unavailable at the time of choice. They occupy different positions in the attribute space, and their unavailability can be either known or unknown to individuals. Although different theories have offered explanations for the influence that phantoms exert on individual choices, they have largely overlooked phantom knowledge. Contradictory predictions can be drawn from these theories, and none provides a good account of the pattern of effects that emerges from our data. We suggest that these contradictions appear because the different theories do not address phantom location and knowledge jointly. When considering phantom knowledge together with location, we observe a consistent overall pattern of effects that encompasses all predictions that could be made on the basis of each theory. We find that known phantoms are stronger when close, and favor the target product, whereas unknown phantoms are stronger when far, and favor the competitor. Finally, we look beyond shifts in choice shares and find that phantom decoys can also affect individuals' post‐choice evaluations and reactions in terms of perceived justice, decision satisfaction, and repatronage intention. Our results show that post‐choice evaluations are driven by phantom knowledge, not phantom location. Copyright © 2012 John Wiley & Sons, Ltd.     

Photopic visual phantom illusion: its common and unique characteristics as a completion effect

An illusion similar to the stationary visual phantom illusion presented earlier by Gyoba (1983, Vision Research 23 205-211) is reported. This illusion is visible in photopic vision and we have tentatively named it the 'photopic phantom illusion'. A typical example of this illusion is a white and light-gray square-wave grating occluded by a black region. In this figure, a phantom grating running across the occluder with clear contours but less contrast, is seen. The critical spatial frequencies of photopic phantoms have been measured and compared with those of scotopic phantoms that have been reported previously, revealing a great resemblance between them. We discuss the characteristics of this illusion in terms of transparency, stereoscopic viewing, and perceptual completion.     

The impact of phantom decoys on choices in cats

Context-dependent choice is an important aspect of decision making. The paper examines context-dependent choice in cats (Felis catus), with particular reference to the effect of local context, on the basis of hypotheses developed in the field of human decision making. Cats were initially confronted with two different feeding options. This binary choice set was later manipulated incorporating a decoy that was better than the available options but ultimately unavailable (a phantom). By means of a within-subjects manipulation of phantom location in the attribute space, the author compared the effects of close and distant phantoms on the final choices. The main finding is that close phantom decoys affected choice behavior of cats by altering the overall share of the available options, leading some animals to reject even some of the available feeding options, and by causing the animals to favor the available option that was more similar to the phantom decoy. No significant effects emerged for phantoms that were far from the alternatives in the attribute space. The strengths of this paper lie in its novel approach and high originality. No other study has used dominating decoys with animals or decoys that are unattainable. This paper provides strong links to the human decision making literature, the presentation of the predictions of a range of different choice models, and the novelty of the application to animals. The use of a phantom decoy is particularly interesting because the phantom cannot actually be chosen, and thus the binary and trinary choice sets both have the very same choices available. Overall, the effect of phantoms is real, interesting and new.     

Floating worlds and their phantoms in the aftermath of social catastrophes

In this paper the author describes certain kinds of images (phantoms) that appear in the aftermath of social catastrophes. These phantoms come with an underlying narrative structure, which the author describes as phantom narratives. Phantom narratives show how the unconscious, working at the group and individual levels, provides political and social contexts within which the individual may find a different kind of containment for these catastrophes. In this way their suffering may be potentially processed psychologically and related to symbolically.     

Immersive virtual reality as a rehabilitative technology for phantom limb experience: a protocol.

This paper describes a study protocol to investigate the use of immersive virtual reality as a treatment for amputees' phantom limb pain. This work builds upon prior research using mirror box therapy to induce vivid sensations of movement originating from the muscles and joints of amputees' phantom limbs. The present project transposes movements of amputees' anatomical limbs into movements of a virtual limb presented in the phenomenal space of their phantom limb. It is anticipated that the protocol described here will help reduce phantom limb pain.     

Body image and cosmetic medical treatments

Cosmetic medical treatments have become increasingly popular over the past decade. The explosion in popularity can be attributed to several factors—the evolution of safer, minimally invasive procedures, increased mass media attention, and the greater willingness of individuals to undergo cosmetic procedures as a means to enhance physical appearance. Medical and mental health professionals have long been interested in understanding both the motivations for seeking a change in physical appearance as well as the psychological outcomes of these treatments. Body image has been thought to play a key role in the decision to seek cosmetic procedures, however, only recently have studies investigated the pre- and postoperative body image concerns of patients. While body image dissatisfaction may motivate the pursuit of cosmetic medical treatments, psychiatric disorders characterized by body image disturbances, such as body dysmorphic disorder and eating disorders, may be relatively common among these patients. Subsequent research on persons who alter their physical appearance through cosmetic medical treatments are likely provide important information on the nature of body image.     

A historical review of long-term visual-transposition research in Japan

Since 1960, more than 37 long-term experiments have been performed in Japan concerning up-down and left-right reversal and inversion, yet these contributions to a field of study pioneered by Stratton 100 years ago remain unfamiliar outside Japan, as most articles have not appeared in English. Japanese researchers have focused on several basic elements of perceptual systems, such as intersensory relationships, sensory-motor coordination, spatial frames of reference, and position constancy. Although subjects have not adapted perfectly to a transposed world in the course of these two- or three-week scale experiments, important data, particularly concerning left-right reversed vision, have been generated. I, myself, have conducted all three types of visual transposition experiments a number of times and propose a model comprised of three subsystems: that is, top-down, bottom-up, and sensory-motor systems. Central to my theory is the notion that the essential change has occurred in the subject's own body image, and that the spatial representation of the body image is visual in nature, not non-visual proprioception (as deduced from Harris' (1965) hypothesis).     

Wearable strain sensor suit for infants to measure limb movements under interaction with caregiver

Development of motion capture technology has enabled the measurement of body movements over long periods of time in daily life. Although accelerometers have been used as primary sensors, problems arise when they are used to measure the movements of infants. Because infants and caregivers interact frequently, accelerometer data from infants may be significantly distorted by a caregiver’s movement. To overcome this problem, a strain sensor suit was developed for infants to measure flexion and extension movements of the limbs. A case study was performed to analyze the strain sensor data of an infant in relation to the accelerometer data of the infant’s and a caregiver’s body under various types of infant–caregiver interaction. The results demonstrated that the strain sensor data had low correlation with the accelerometer data of the infant and caregiver while the accelerometer data between infant and caregiver had higher correlation. This suggests that the strain sensor is suitable to detect limbs’ angular displacements mostly independent from the translational body movements exerted by a caregiver.     

Moving phantom visibility as a function of fundus pigmentation

Moving phantom visibility was measured for subjects with a fundus classified as either lightly or darkly pigmented. The phantom-inducing pattern was a black-and-white square-wave grating drifting continuously from left to right, with a black horizontal occluder interrupting the middle of the grating. Moving phantom visibility was significantly reduced for darker relative to lighter pigmented subjects. The results show that fundus pigmentation can influence the perception of illusory contours and surfaces (i.e., phantoms). This finding supports and expands on previous research concerning fundus pigmentation influences on real contour perception.     

Virtual Reality Based Treatments in Eating Disorders and Obesity: A Review

Since the late 1990s the use of virtual reality (VR) has expanded in the field of mental disorders. During this time, several VR-based applications have been developed for the treatment of eating disorders (ED) and obesity. Both these pathologies involve disturbances related to eating behavior, weight, and body image. Although effective and well-established protocols are now available for the treatment of ED and obesity, relapses are frequent and a proportion of patients do not improve after intervention. In this context, VR has been shown to be a useful technology for enhancing traditional cognitive-oriented therapies. The main objective of this review was therefore to examine the evidence regarding the efficacy of VR-based treatments as a component of therapeutic interventions for ED and obesity. To this end, three databases (PsycInfo, Medline, and PsycArticles) were searched for the period 1986–2012. Only research articles and case studies were selected. Although several methodological deficiencies were detected in the reviewed studies, there is fair evidence for the effectiveness of VR-based treatments in ED and obesity. VR-based interventions usually combine exposure to VR environments with cognitive therapies. The VR component seems to be especially suitable for reducing body image disturbances, such as body image dissatisfaction, and for increasing self-esteem and self-efficacy. The rationale for the use of VR in these areas is also presented and discussed.     

Body representations and cognitive ontology: Drawing the boundaries of the body image

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 et al. (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.     

Perceptual continuation and depth in visual phantoms can be explained by perceptual transparency

We try to explain perceptual continuation and depth in the visual-phantom illusion in terms of perceptual transparency. Perceptual continuation of inducing gratings across the occluder in stationary phantoms could be explained with unique transparency, a notion proposed by Anderson (1997 Perception 26 419-453). This view is consistent with a number of previous reports including that of McCourt (1994 Vision Research 34 1609-1617) who criticized the stationary phantom illusion from the viewpoint of his counterphase lightness induction or grating induction, which might involve invalid transparency. Here we confirm that the photopic phantom illusion (Kitaoka et al, 1999 Perception 28 825-834) really gives in-phase lightness induction and involves bistable transparency. It is thus suggested that perceptual continuation and depth in the visual-phantom illusion depend on perceptual transparency.     

The use of virtual reality in the study, assessment, and treatment of body image in eating disorders and nonclinical samples: a review of the literature

This article reviews research into the use of virtual reality in the study, assessment, and treatment of body image disturbances in eating disorders and nonclinical samples. During the last decade, virtual reality has emerged as a technology that is especially suitable not only for the assessment of body image disturbances but also for its treatment. Indeed, several virtual environment-based software systems have been developed for this purpose. Furthermore, virtual reality seems to be a good alternative to guided imagery and in vivo exposure, and is therefore very useful for studies that require exposure to life-like situations but which are difficult to conduct in the real world. Nevertheless, review highlights the lack of published controlled studies and the presence of methodological drawbacks that should be considered in future studies. This article also discusses the implications of the results obtained and proposes directions for future research.     

A Brief History of Research on Phantom Alternatives: Evidence for Seven Empirical Generalizations About Phantoms

Phantom alternatives (unavailable options) can appear in many common decision tasks and can influence a wide variety of everyday behaviors. Although the term phantom is of recent vintage, researchers have investigated psychological reactions to unavailable alternatives for almost 60 years. In this article, we review 13 domains of research on unavailable alternatives to identify seven empirical generalizations about phantoms, These generalizations call into questions some basic assumptions of formal choice theory and suggest new research directions for studying phantom options.     

体像困扰与社会文化因素

数据显示大多数人对自己的体像不满意,而对体像的不满意可能形成困扰。存在体像困扰的个体更多体验抑郁、焦虑等负面情绪,且体像困扰和进食障碍、体像障碍等精神疾病均存在密切的关系。在介绍概念的同时,本文还对体像困扰相关社会文化因素的影响进行了综述。已有研究表明女性较男性更容易受到体像困扰的影响;体像困扰存在跨文化的一致性,也存在文化差异;家庭、同伴和媒体对于体像困扰均有影响。     

Abnormalities in the awareness of action

Optimal motor control relies on internal representations of the actual, desired and predicted states of our limbs and the external world. Only certain components of these internal representations are available to awareness. We suggest that impairments of the components of internal representations might underlie a broad variety of neuropsychiatric symptoms, including the anarchic hand sign, phantom limbs, utilization behaviour and delusions of control.