Sensorimotor Body Research Articles

The bodily fundament of empathy: The role of action, nonaction-oriented, and interoceptive body representations.

Mental representations with bodily contents or in various bodily formats have been suggested to play a pivotal role in social cognition, including empathy. However, there is a lack of systematic studies investigating, in the same sample of participants and using an individual differences approach, whether and to what extent the sensorimotor, perceptual, and interoceptive representations of the body could fulfill an explanatory role in the empathic abilities.To address this goal, we carried out two studies in which healthy adults were given measures of interoceptive sensibility (IS), action (aBR), and nonaction-oriented body representations (NaBR), and affective, cognitive, and motor empathy. A higher tendency to be self-focused on interoceptive signals predicted higher affective, cognitive, and motor empathy levels. A better performance in tasks probing aBR and NaBR predicted, respectively, higher motor and cognitive empathy levels.These findings support the view that the various facets of the empathic response are differently grounded in the body since they diversely involve representations with a different bodily format.Individual differences in the focus on one's internal body state representation can directly modulate all the components of the empathic experience. Instead, a body representation used interpersonally to represent both one's own body and others' bodies, in particular in its spatial specificity, could be necessary to accurately understand other people's minds (cognitive empathy), while a sensorimotor body representation used to represent both one's own body and others' bodies actions, could be fundamental for the self-awareness of feelings expressed in actions (motor empathy).

Structural representations of fingers rely on both anatomical and spatial reference frames.

Finger agnosia refers to a neurological condition in which patients with left posterior parietal lesions fail to identify their fingers, despite having relatively preserved abilities in sensation and skilled action. This dissociation suggests that the structural body representations (BSRs) may be distinct from sensorimotor representations. However, recent research has reported that postural changes modulate representation of hand structure, revealing dynamic interactions between structural and sensorimotor body representations. However, it is unknown how and to what extent anatomical and spatial proximity contribute to shape the hand structural representation. We investigate this question using the "in-between" test in which participants estimate how many unstimulated fingers are in between 2 touched fingers of the left hand placed palm down. The first phalange of the participants' fingers was touched on the left or right side. Judged finger numerosity was greater when fingers were stimulated on far sides (i.e., opposite sides of the 2 fingers) compared to when they were stimulated on close (i.e., sides facing each other's) or middistance (i.e., sides facing in the same direction) sides. Therefore, finger identification was modulated by anatomical and spatial proximity in external space between touches. This demonstrates that BSRs rely on both anatomical and external reference frames. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Tool Use Modulates Somatosensory Cortical Processing in Humans.

Tool use leads to plastic changes in sensorimotor body representations underlying tactile perception. The neural correlates of this tool-induced plasticity in humans have not been adequately characterized. This study used ERPs to investigate the stage of sensory processing modulated by tool use. Somatosensory evoked potentials, elicited by median nerve stimulation, were recorded before and after two forms of object interaction: tool use and hand use. Compared with baseline, tool use-but not use of the hand alone-modulated the amplitude of the P100. The P100 is a mid-latency component that indexes the construction of multisensory models of the body and has generators in secondary somatosensory and posterior parietal cortices. These results mark one of the first demonstrations of the neural correlates of tool-induced plasticity in humans and suggest that tool use modulates relatively late stages of somatosensory processing outside primary somatosensory cortex. This finding is consistent with what has been observed in tool-trained monkeys and suggests that the mechanisms underlying tool-induced plasticity have been preserved across primate evolution.

12.4 THE BODILY SELF IN PSYCHOSIS: SENSORIMOTOR INDUCTION OF AUDITORY MISATTRIBUTION IN PSYCHOSIS IS LINKED TO NEURAL DISCONNECTIVITY

Abstract Background Psychosis is often depicted as a disruption of the self-model. Patients suffering from psychosis report many symptoms relating to deficiencies in the minimal self, including loss of the sense of control over their actions (Sense of Agency) as well as numerous disturbances of body representation (e.g. Body Ownership). Positive symptoms of psychosis such as passivity symptoms and auditory hallucinations (termed first-rank symptoms) are characterized by a diminished demarcation of self-other boundaries, causing misattribution of self-generated actions to external sources. It has been suggested that this deficiency in self-monitoring in schizophrenia is due to abnormal sensorimotor prediction mechanisms, causing a loss of agency for actions and thoughts. While the neurobiological underpinnings of schizophrenia are yet unclear, many studies have reported aberrant neural connectivity in schizophrenia patients which may impact sensorimotor prediction and integration. Methods Recently, we have shown that introducing sensorimotor conflict (SMC) can induce psychosis like symptoms in healthy patients. Employing a master-slave robotic system we induced a conflict by introducing a delay between the participants’ movements and the haptic feedback. The SMC caused a feeling of a Presence (FoP) which is a first rank symptom of psychosis. The FoP is also found in neurological patients with lesions in cortical regions of the temporoparietal cortex, insular cortex and fronto-parietal cortex related to abnormal bodily self-representation. Here, we tested if SMC may cause misattribution of auditory stimuli and if this is related to neural connectivity. We tested first episode psychosis patients (N=31) with and without first rank symptoms (related to the sense of control over actions and thoughts) as well as healthy participants (N=20) on an auditory attribution task while inducing conflict with the master-slave robot. Results We found that when a SMC was introduced patients with first rank symptoms showed a decrease in their ability to judge if the auditory stimuli were in their own voice or the voice of another person. Resting state functional connectivity analysis indicated that the first rank patients had reduced connectivity in the network related to the SMC, but not in other control regions. Furthermore, the reduced functional connectivity correlated with the rates of auditory misattribution. Conclusions Our results show that induction of SMC can cause auditory misattributions, and that this is related to reduced cortical communication in regions related to sensorimotor body representation. These findings connect two influential theories of psychosis linking cognitive theories of sensorimotor prediction error in schizophrenia with systems level theories of neural disconnectivity. Understanding these neurocognitive mechanisms underlying the disruption of the self-model in psychosis may allow novel approaches in early diagnosis and treatment of these conditions.

Motor-based bodily self is selectively impaired in eating disorders.

BackgroundBody representation disturbances in body schema (i.e. unconscious sensorimotor body representations for action) have been frequently reported in eating disorders. Recently, it has been proposed that body schema relies on adequate functioning of the motor system, which is strongly implicated in discriminating between one’s own and someone else’s body. The present study aimed to investigate the motor-based bodily self in eating disorders and controls, in order to examine the role of the motor system in body representation disturbances at the body schema level.MethodFemale outpatients diagnosed with eating disorders (N = 15), and healthy controls (N = 18) underwent a hand laterality task, in which their own (self-stimuli) and someone else’s hands (other-stimuli) were displayed at different orientations. Participants had to mentally rotate their own hand in order to provide a laterality judgement. Group differences in motor-based bodily self-recognition—i.e. whether a general advantage occurred when implicitly processing self- vs. other-stimuli − were evaluated, by analyzing response times and accuracy by means of mixed ANOVAs.ResultsPatients with eating disorders did not show a temporal advantage when mentally rotating self-stimuli compared to other-stimuli, as opposed to controls (F(1, 31) = 5.6, p = 0.02; eating disorders-other = 1092 ±256 msec, eating disorders-self = 1097±254 msec; healthy controls-other = 1239±233 msec, healthy controls -self = 1192±232 msec).ConclusionThis study provides initial indication that high-level motor functions might be compromised as part of body schema disturbances in eating disorders. Further larger investigations are required to test motor system abnormalities in the context of body schema disturbance in eating disorders.

Multiple Perspectives on Body Image Research

Representation of the body is a nuclear aspect of self-image. Body representation includes both subjective and intersubjective experiences. The importance of visual body representation in our social life is demonstrated by the time we spend to take care of our physical appearance, including use of plastic surgery, as well as by the severe mental disorders associated to its alteration, including eating disorders (EDs) and body dysmorphic disorders. In spite of these issues, (neuro)psychological research on body representation has so far mainly focused on the body as a motor device, devoted to the perception of and interaction with objects. The complexity of factors involved in the development, maintenance, and plasticity of body image representations requires an integrated approach that facilitates the evaluation and treatment of EDs with novel, evidence-based, and more efficacious protocols. This special issue of European Psychologist aims to advance such an integrative approach, with a collection of papers that gather different perspectives on the phenomenological, cognitive, (neuro)psychological, and cultural aspects of body representation disorders.

The Conscious Id

Two aspects of the body are represented in the brain, and they are represented differently. The most important difference is that the brain regions for the two aspects of the body are associated with different aspects of consciousness. Very broadly speaking, the brainstem mechanisms derived from the autonomic body are associated with affective consciousness, and the cortical mechanisms derived from the sensorimotor body are associated with cognitive consciousness. Moreover, the upper brainstem is intrinsically conscious whereas the cortex is not; it derives its consciousness from the brainstem. These facts have substantial implications for psychoanalytic metapsychology because the upper brainstem (and associated limbic structures) performs the functions that Freud attributed to the id, while the cortex (and associated forebrain structures) performs the functions he attributed to the ego. This means that the id is the fount of consciousness and the ego is unconscious in itself. The basis for these conclusions, and some of their implications, are discussed here in a preliminary fashion.

Phantom limb pain and bodily awareness

Phantom pain is a frequent consequence of amputation or deafferentation. There are many possible contributing mechanisms, including stump-related pathology, spinal and cortical changes. Phantom limb pain is notoriously difficult to treat. Continued consideration of the factors associated with phantom pain and its treatment is of utmost importance, not only to advance the scientific knowledge about the experience of the body and neuropathic pain, but also fundamentally to promote efficacious pain management. This review first discusses the mechanisms associated with phantom pain and summarizes the current treatments. The mechanisms underlying phantom pain primarily relate to peripheral/spinal dysfunction, and supraspinal and central plasticity in sensorimotor body representations. The most promising methods for managing phantom pain address the maladaptive changes at multiple levels of the neuraxis, for example, complementing pharmacological administration with physical, psychological or behavioural intervention. These supplementary techniques are even efficacious in isolation, perhaps by replacing the absent afferent signals from the amputated limb, thereby restoring disrupted bodily representations. Ultimately, for optimal patient outcomes, treatments should be both symptom and mechanism targeted.

Wherever is my arm? Impaired upper limb position accuracy in Complex Regional Pain Syndrome

Knowledge of the position of one’s limbs is an essential component of daily function and relies on complex interactions of sensorimotor body schema-related information. Those with Complex Regional Pain Syndrome (CRPS) express difficulty in knowing where their affected limb is positioned. The aim of this study was to determine the degree to which experimental data supported the reported difficulty in limb position sense. A controlled experimental design was used to measure upper limb position accuracy amongst those with CRPS of one arm. Position accuracy was individually measured in both arms and compared to a known target position. Video captured each of 36 trials (half with arm in full view and half with vision obscured). The error in degrees between actual and known targets was determined using video analysis software. The Brief Pain Inventory measured pain. A subjective mental image representation of both upper limbs was documented. The CRPS group had moderate pain intensity and were significantly less accurate in positioning both the affected and unaffected limbs compared to controls ( p < 0.001). Position accuracy of the CRPS affected limb significantly improved with vision (8.3° in view, 10.7° not in view). Subjective mental representations of the affected limb were visualised as distorted. Evidence of bilateral arm positioning impairments in unilateral arm CRPS suggests that central mechanisms are involved. Cortical reorganisation in regions associated with the body schema (i.e. primary somatosensory and parietal cortices) is proposed as an explanation. The exact relationship between pain and limb position deficits requires further exploration.

Exploring Links Between Sensorimotor and Visuospatial Body Representations in Infancy

The aim of this study was to explore whether sensorimotor and visuospatial body representations interact in early development. Sixty-two infants between 6 and 15 months of age were tested for visuospatial body representations via a human body visual discrimination task. Their motor activity during the discrimination task, as well as motor development and imitation skill, were assessed as indexes of sensorimotor body representations. Based on research with adults, we predicted inter-correlations between performance on the visuospatial body task and infants' sensorimotor development; however, no significant associations were observed. Discussion speculates on developmental trajectories for these two distinct body representation systems.

Kinesthetic Imagery and Tool-Specific Modulation of Corticospinal Representations in Expert Tennis Players

Specific physical or mental practice may induce short- and long-term neuroplastic changes in the motor system and cause tools to become part of one's own body representation. Athletes who use tools as part of their practice may be an excellent model for assessing the neural correlates of possible bodily representation changes that are specific to extensive practice. We used single-pulse transcranial magnetic stimulation to measure corticospinal excitability in forearm and hand muscles of expert tennis players and novices while they mentally practiced a tennis forehand, table tennis forehand, and a golf drive. The muscles of expert tennis players showed increased corticospinal facilitation during motor imagery of tennis but not golf or table tennis. Novices, although athletes, were not modulated across sports. Subjective reports indicated that only in the tennis imagery condition did experts differ from novices in the ability to form proprioceptive images and to consider the tool as an extension of the hand. Neurophysiological and subjective data converge to suggest a key role of long-term experience in modulating sensorimotor body representations during mental simulation of sports.

Origins and early development of human body knowledge.

As a knowable object, the human body is highly complex. Evidence from several converging lines of research, including psychological studies, neuroimaging and clinical neuropsychology, indicates that human body knowledge is widely distributed in the adult brain, and is instantiated in at least three partially independent levels of representation. Sensorimotor body knowledge is responsible for on-line control and movement of one's own body and may also contribute to the perception of others' moving bodies; visuo-spatial body knowledge specifies detailed structural descriptions of the spatial attributes of the human body; and lexical-semantic body knowledge contains language-based knowledge about the human body. In the first chapter of this Monograph, we outline the evidence for these three hypothesized levels of human body knowledge, then review relevant literature on infants' and young children's human body knowledge in terms of the three-level framework. In Chapters II and III, we report two complimentary series of studies that specifically investigate the emergence of visuo-spatial body knowledge in infancy. Our technique is to compare infants'responses to typical and scrambled human bodies, in order to evaluate when and how infants acquire knowledge about the canonical spatial layout of the human body. Data from a series of visual habituation studies indicate that infants first discriminate scrambled from typical human body picture sat 15 to 18 months of age. Data from object examination studies similarly indicate that infants are sensitive to violations of three-dimensional human body stimuli starting at 15-18 months of age. The overall pattern of data supports several conclusions about the early development of human body knowledge: (a) detailed visuo-spatial knowledge about the human body is first evident in the second year of life, (b) visuo-spatial knowledge of human faces and human bodies are at least partially independent in infancy and (c) infants' initial visuo-spatial human body representations appear to be highly schematic, becoming more detailed and specific with development. In the final chapter, we explore these conclusions and discuss how levels of body knowledge may interact in early development.