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The Rubber Hand Illusion “It belongs to me, but it is not mine”
Abstract
Az alábbi összefoglaló BOTVINICK és COHEN (1998) a testélményzavarok diagnosztikájában szerzett tapasztalatai alapján konstruált „Műkéz Illúziót“ mutatja be. A testélmény kiindulópontja a személyes szenzomotoros tapasztalatokból származó testséma, mely a testképpel való integrációban hozza létre az identitás és a sajáttestélmény ötvözetét. Adódnak azonban olyan neuropszichológiai zavarok, pszichiátriai betegségek vagy normál tudatállapotban is felbukkanó jelenségek, melynek során az ember úgy érzi, mintha a teste nem lenne az övé, más esetben pedig azt érzi, hogy saját testének egyes részei elszakadnak tőle, deperszonalizálódnak. A testkép és a testséma mindennapi élethelyzetben is disszociálódhat. Ilyenkor a test más részeihez mérten megváltozik egy-egy testrész hőmérséklete, fájdalomküszöbe és a környezeti toxinokra adott immunválasz mértéke.A bemutatandó „Műkéz Illúzió“ (Rubber Hand Illusion, RHI) kiváltási körülményei, az élmény nyelvi kifejezésformája és a kiváltás mértékével arányos fiziológiai változások ismerete, véleményünk szerint megnyitja az utat a testélmény patológiák részletesebb kognitív neuropszichológiai elemzéséhez, egészséges, pszichoszomatikus és pszichiátriai betegségektől szenvedő személyek esetében egyaránt. A vizsgálati paradigma kiterjedtebb kutatási felhasználása mélyebb bepillantást enged az empátia és az én és a másik elhatárolódási folyamat megértésébe. Az RHI klinikai alkalmazása hozzájárulhat egyes szelffejlődési zavarok dinamikájának vizsgálatához, valamint lehetővé teszi a kognitív terápiás eszköztár bővítését is.
A virtuális valóságban (VR) végzett gyógyászati és oktatási tevékenység iránt megnövekedett érdeklődés szükségessé teszi a VR-re vonatkozó pszichológiai értelmezési keretek egy csoportjának bemutatását. Az összefoglalóban – szakirodalmi ismeretekre hagyatkozva – a belemerülés (immersion), valamint a jelenlét (presence) fogalmak rövid bemutatását követően a virtuális valóság mentális modelljei közül elsősorban a téri reprezentációra vonatkozó komponenseket fogom bemutatni. Az áttekintés a VR-ben megjelenő multiszenzoros koherencia, tudatos jelenlét, kapcsolat és leválás, átmeneti jelenlét és a különböző affordanciák szerepének ismertetésére koncentrál. Az alkalmazások fejezetrészben pedig néhány, az egészségügyben és az oktatásügyben alkalmazott, és várhatóan az eddigi gyakorlathoz viszonyítva szélesebb körben hazánkban is alkalmazandó VR-alapú eljárások ismertetésére kerül sor. A digitális oktatás és a pszichoterápiás ellátás iránti érdeklődés ellentmondásos. Sokan a klienssel vagy a tanulóval való személyes kapcsolat elvesztésének fenyegető veszélyétől féltik az orvosokat és a pedagógusokat. A betegek és a diákok részéről azonban egyre sürgetőbb az igény a VR-hez kötődő módszerek bevezetésére. A bemutatott összefoglaló tovább erősíti az új digitális eszközök alkalmazásával kapcsolatos igényeket, de ugyanakkor felhívja a figyelmet, hogy szükség van olyan technikai és szaktudományi infrastruktúra megteremtésére, amely kritikus elemzést követően képes elősegíteni a jelenlegi, konfliktusokkal terhes ellátási és oktatási formák fejlődését. Az új VR-módszerek bevezetése a tudomány és a gyakorlat közös feladata.
In functional neuroimaging studies, self-specificity has been investigated by contrasting other-relevant processing against the self. Our meta-analysis investigates self-specificity with respect to degrees of self-relatedness (SR) of the other (i.e. close and public other). Literature suggests a dorsal-ventral component of self- and other-reflection within the MPFC, which has yet to be analyzed according to varying SR, nor has it been quantified statistically. In the present meta-analysis, we pursued three main objectives. First, we conducted whole-brain ALE meta-analyses using contemporary literature analyzing self>close other and self>public other contrasts to determine self-specific regions sensitive to SR. Next, we conducted ALE and conjunction analyses of studies employing self>control, close other>control, or public other>control contrasts to determine shared regions of activation. Third, we conducted post hoc analyses to quantify any observed dorsal-ventral distinction, employing novel methodology using a surface-based coordinates system. We observed significant activation in the dACC and vACC for self>close other and self>public other, whereas anterior insula was observed only for self>public other. An MPFC dorsal-ventral distinction was observed and quantified whereby public other>control was significantly more dorsal than self>control and close other>control. Our results are discussed with regards to SR. Prospective avenues of research exploiting our methodology are proposed.
Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body. This is achieved by full-body ownership illusions which make use of specific patterns of visual and somatic stimuli integration. Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self. We quantified the strength of the body-swap illusion in conditions where the participants were observing this artificial body from the perspective of the first or third person. Consistent results from subjective reports and physiological recordings show that the first person visual perspective is critical for the induction of this full-body ownership illusion. This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.
A growing body of evidence suggests that empathy for pain is underpinned by neural structures that are also involved in the direct experience of pain. In order to assess the consistency of this finding, an image-based meta-analysis of nine independent functional magnetic resonance imaging (fMRI) investigations and a coordinate-based meta-analysis of 32 studies that had investigated empathy for pain using fMRI were conducted. The results indicate that a core network consisting of bilateral anterior insular cortex and medial/anterior cingulate cortex is associated with empathy for pain. Activation in these areas overlaps with activation during directly experienced pain, and we link their involvement to representing global feeling states and the guidance of adaptive behavior for both self- and other-related experiences. Moreover, the image-based analysis demonstrates that depending on the type of experimental paradigm this core network was co-activated with distinct brain regions: While viewing pictures of body parts in painful situations recruited areas underpinning action understanding (inferior parietal/ventral premotor cortices) to a stronger extent, eliciting empathy by means of abstract visual information about the other's affective state more strongly engaged areas associated with inferring and representing mental states of self and other (precuneus, ventral medial prefrontal cortex, superior temporal cortex, and temporo-parietal junction). In addition, only the picture-based paradigms activated somatosensory areas, indicating that previous discrepancies concerning somatosensory activity during empathy for pain might have resulted from differences in experimental paradigms. We conclude that social neuroscience paradigms provide reliable and accurate insights into complex social phenomena such as empathy and that meta-analyses of previous studies are a valuable tool in this endeavor.
In patient studies, impairments of sense of body ownership have repeatedly been linked to right-hemispheric brain damage. To test whether a right-hemispheric dominance for sense of body ownership could also be observed in healthy adults, the rubber hand illusion was elicited on both hands of 21 left-handers and 22 right-handers. In this illusion, a participant's real hand is stroked while hidden from view behind an occluder, and a nearby visible hand prosthesis is repeatedly stroked in synchrony. Most participants experience the illusionary perception of touch sensations arising from the prosthesis. The vividness of the illusion was measured by subjective self-reports as well as by skin conductance responses to watching the rubber hand being harmed. Handedness did not affect the vividness of the illusion, but a stronger skin conductance response was observed, when the illusion was elicited on the left hand. These findings suggest a right-hemispheric dominance for sense of body ownership in healthy adults.
Self-face recognition is crucial for sense of identity and self-awareness. Finding self-face recognition disorders mainly in neurological and psychiatric diseases suggests that modifying sense of identity in a simple, rapid way remains a "holy grail" for cognitive neuroscience. By touching the face of subjects who were viewing simultaneous touches on a partner's face, we induced a novel illusion of personal identity that we call "enfacement": The partner's facial features became incorporated into the representation of the participant's own face. Subjects reported that morphed images of themselves and their partner contained more self than other only after synchronous, but not asynchronous, stroking. Therefore, we modified self-face recognition by means of a simple psychophysical manipulation. While accommodating gradual change in one's own face is an important form of representational plasticity that may help maintaining identity over time, the surprisingly rapid changes induced by our procedure suggest that sense of facial identity may be more malleable than previously believed. "Enfacement" correlated positively with the participant's empathic traits and with the physical attractiveness the participants attributed to their partners. Thus, personality variables modulate enfacement, which may represent a marker of the tendency to be social and may be absent in subjects with defective empathy.
Depersonalisation disorder is characterised by emotion suppression, but the cerebral mechanisms of this symptom are not yet fully understood.
To compare brain activation and autonomic responses of individuals with the disorder and healthy controls.
Happy and sad emotion expressions in increasing intensities (neutral to intense) were presented in an implicit event-related functional magnetic resonance imaging (fMRI) design with simultaneous measurement of autonomic responses.
Participants with depersonalisation disorder showed fMRI signal decreases, whereas the control group showed signal increases in response to emotion intensity increases in both happy and sad expressions. The analysis of evoked haemodynamic responses from regions exhibiting functional connectivity between central and autonomic nervous systems indicated that in depersonalisation disorder initial modulations of haemodynamic response occurred significantly earlier (2 s post-stimulus) than in the control group (4-6 s post-stimulus).
The results suggest that fMRI signal decreases are possible correlates of emotion suppression in depersonalisation disorder.
We examined the ability of a patient, who had a cerebral lesion involving the left posterior hemisphere, to identify and to localize stimuli applied to her "deafferented" right upper limb. We observed a functional dissociation between localization and identification in both performance and subjective report. This finding may be a tactual analogue of "blind sight."
In primates, the premotor cortex is involved in the sensory guidance of movement. Many neurons in ventral premotor cortex
respond to visual stimuli in the space adjacent to the hand or arm. These visual receptive fields were found to move when
the arm moved but not when the eye moved; that is, they are in arm-centered, not retinocentric, coordinates. Thus, they provide
a representation of space near the body that may be useful for the visual control of reaching.
The neuropsychological literature on 3-D spatial interactions is integrated using a model of 4 major behavioral realms: (a) peripersonal (visuomotor operations in near-body space), (b) focal extrapersonal (visual search and object recognition), (c) action extrapersonal (orienting in topographically defined space), and (d) ambient extrapersonal (orienting in earth-fixed space). Each is associated with a distinct cortical network: dorsolateral peripersonal, predominantly ventrolateral focal-extrapersonal, predominantly ventromedial action-extrapersonal, and predominantly dorsomedial ambient-extrapersonal systems. Interactions in 3-D space are also regulated neurochemically with dopaminergic and cholinergic excitation associated with extrapersonal activation and noradrenergic and serotonergic excitation associated with peripersonal activation. This model can help explain the 3-D imbalances in prominant neuropsychological disorders.
Previous findings have demonstrated the existence of a visual peripersonal space centered on the hand in humans and its modulatory effects on tactile perception. A strong modulatory effect of vision on touch perception was found when a visual stimulus was presented near the hand. In contrast, when the visual stimulus was presented far from the hand, only a weak modulatory effect was found. The aim of the present study was to verify whether such cross-modal links between touch and vision in the peripersonal space centered on the hand could be mediated by proprioceptive signals specifying the current hand positions or if they directly reflect an interaction between two sensory modalities, i.e., vision and touch. To this aim, cross-modal effects were studied in two different experiments: one in which patients could see their hands and one in which vision of their hands was prevented. The results showed strong modulatory effects of vision on touch perception when the visual stimulus was presented near the seen hand and only mild effects when the vision of the hand was prevented. These findings are explained by referring to the activity of bimodal neurons in premotor and parietal cortex of macaque, which have tactile receptive fields on the hand, and corresponding visual receptive fields in the space immediately adjacent to the tactile fields. One important feature of these bimodal neurons is that their responsiveness to visual stimuli delivered near the body part is reduced or even extinguished when the view of the body part is prevented. This implies that, at least for the hand, the vision of the hand is crucial for determining the spatial mapping between vision and touch that takes place in the peripersonal space. In contrast, the proprioceptive signals specifying the current hand position in space do not seem to be relevant in determining the cross-modal interaction between vision and touch.
The goal of this study was to assess brain glucose metabolism and its relationship to dissociation measures and clinical symptoms in DSM-IV depersonalization disorder.
Positron emission tomography scans coregistered with magnetic resonance images of eight subjects with depersonalization disorder were compared to those of 24 healthy comparison subjects. The two groups did not differ in age, sex, education, performance on a baseline neuropsychological battery, or performance on a verbal learning task administered during [(18)F]fluorodeoxyglucose uptake. A cortical analysis by individual Brodmann's areas was performed.
Compared to the healthy subjects, subjects with depersonalization disorder showed significantly lower metabolic activity in right Brodmann's areas 22 and 21 of the superior and middle temporal gyri and had significantly higher metabolism in parietal Brodmann's areas 7B and 39 and left occipital Brodmann's area 19. Dissociation and depersonalization scores among the subjects with depersonalization disorder were significantly positively correlated with metabolic activity in area 7B.
Depersonalization appears to be associated with functional abnormalities along sequential hierarchical areas, secondary and cross-modal, of the sensory cortex (visual, auditory, and somatosensory), as well as areas responsible for an integrated body schema. These findings are in good agreement with the phenomenological conceptualization of depersonalization as a dissociation of perceptions as well as with the subjective symptoms of depersonalization disorder.
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.
Watching a rubber hand being stroked, while one's own unseen hand is synchronously stroked, may cause the rubber hand to be attributed to one's own body, to "feel like it's my hand." A behavioral measure of the rubber hand illusion (RHI) is a drift of the perceived position of one's own hand toward the rubber hand. The authors investigated (a) the influence of general body scheme representations on the RHI in Experiments 1 and 2 and (b) the necessary conditions of visuotactile stimulation underlying the RHI in Experiments 3 and 4. Overall, the results suggest that at the level of the process underlying the build up of the RHI, bottom-up processes of visuotactile correlation drive the illusion as a necessary, but not sufficient, condition. Conversely, at the level of the phenomenological content, the illusion is modulated by top-down influences originating from the representation of one's own body.
Inferior parietal lobule (IPL) neurons were studied when monkeys performed motor acts embedded in different actions and when
they observed similar acts done by an experimenter. Most motor IPL neurons coding a specific act (e.g., grasping) showed markedly
different activations when this act was part of different actions (e.g., for eating or for placing). Many motor IPL neurons
also discharged during the observation of acts done by others. Most responded differentially when the same observed act was
embedded in a specific action. These neurons fired during the observation of an act, before the beginning of the subsequent
acts specifying the action. Thus, these neurons not only code the observed motor act but also allow the observer to understand
the agent's intentions.
Recent imaging results suggest that individuals automatically share the emotions of others when exposed to their emotions. We question the assumption of the automaticity and propose a contextual approach, suggesting several modulatory factors that might influence empathic brain responses. Contextual appraisal could occur early in emotional cue evaluation, which then might or might not lead to an empathic brain response, or not until after an empathic brain response is automatically elicited. We propose two major roles for empathy; its epistemological role is to provide information about the future actions of other people, and important environmental properties. Its social role is to serve as the origin of the motivation for cooperative and prosocial behavior, as well as help for effective social communication.
The capacity to use tools is a fundamental evolutionary achievement. Its essence stands in the capacity to transfer a proximal goal (grasp a tool) to a distal goal (e.g., grasp food). Where and how does this goal transfer occur? Here, we show that, in monkeys trained to use tools, cortical motor neurons, active during hand grasping, also become active during grasping with pliers, as if the pliers were now the hand fingers. This motor embodiment occurs both for normal pliers and for “reverse pliers,” an implement that requires finger opening, instead of their closing, to grasp an object. We conclude that the capacity to use tools is based on an inherently goal-centered functional organization of primate cortical motor areas.
• neurophysiology
• tool use
• goal coding
• motor act
Previous research has examined neural responses to threatening facial expressions such as those displaying anger, fear, and disgust. Here, we examined neural responses to a different type of threatening facial expression that primarily signifies a threat to social connection, namely a "disapproving" facial expression. We hypothesized that neural responses to disapproving facial expressions would be moderated by individual differences in rejection sensitivity. Using functional magnetic resonance imaging (fMRI), we scanned participants while they viewed brief video clips of facial expressions depicting disapproval, anger, and disgust. As expected, all three expressions yielded bilateral amygdala activation relative to a resting baseline. Additionally, individuals who scored higher on a measure of rejection sensitivity exhibited greater dorsal anterior cingulate cortex activity in response to disapproving facial expressions, but not in response to anger or disgust facial expressions. Results suggest that, at the neural level, individuals high in rejection sensitivity may be more sensitive to facial expressions signaling potential rejection, but not to threatening facial expressions in general. Results also suggest that disapproving facial expressions convey a distinct type of threat and should be considered in future studies of socially threatening facial expressions.
The Oxford Handbook of Hypnosis is a comprehensive summary of where field of hypnosis has been, where it stands today, and its future directions. The book's articles on the scientific background to the field, aim to live up to an uncompromising scholarly legacy. In addition, the scope of the book includes seventeen clinical articles which describe how hypnosis is best used with patients across a spectrum of disorders and applied settings.
This chapter suggests that the need for social connection is a fundamental need and that like other basic needs, a lack of social connection can feel "painful" an experience that has been termed "social pain". It reviews two studies that utilized functional neuroimaging methodologies to examine whether the dorsal portion of the anterior cingulate cortex (dACC) is sensitive to: (1) the experience of social pain in humans and (2) cues that predict social pain in humans ("disapproving facial expressions"). A third study examined the extent to which sensitivity to one type of pain relates to sensitivity to the other, as well as whether activating one type of pain heightens sensitivity to the other. The chapter then highlights some of the extensions of this work by reviewing three studies that examined whether neural responses to social pain relate to and can help us understand real-world social phenomena.
Az emberi arcfelismeres neuralis korrelatumait szamos elektro- es pszichofizikai kiserlet keresi. Elektrofiziologiai vizsgalatok leirtak, hogy az okcipito-temporalis teruletek felől elvezethető egy nagy negativ hullam, mely latenciaja miatt az N170 nevet kapta. Szamos tanulmany szerint az N170 speci_
Illusions have historically been of great use to psychology for what they can reveal about perceptual processes. We report here an illusion in which tactile sensations are referred to an alien limb. The effect reveals a three-way interaction between vision, touch and proprioception, and may supply evidence concerning the basis of bodily self-identification.
In this paper we shall argue that mentalistic action explanations, which form an essential component of a mature theory of mind, are conceptually and developmentally derived from an earlier and purely teleological interpretational system present in infancy. First we summarize our evidence demonstrating teleological action explanations in one-year-olds. Then we shall briefly contrast the structure of teleological vs. causal mentalistic action explanations and outline four logical possibilities concerning the nature of the developmental relationship between them. We shall argue for the view that causal mentalistic action explanations are constructed as useful theoretical extensions of the earlier, purely teleological, nonmentalistic interpretational stance.
Here, we assess the usefulness of first-person methods for the study of embodiment during the rubber hand illusion (RHI).
Participants observed a rubber hand being stroked synchronously and asynchronously with their concealed hand after which they
made proprioceptive judgments about the location of their hand and completed a self-report questionnaire. A randomly selected
cohort was further interviewed during the illusion and their transcripts analyzed using interpretative phenomenological analysis
(IPA). Results showed that the IPA group experienced a more intense embodied experience during the RHI, measured by proprioceptive
distortion and self-report. IPA revealed four main themes of embodied experience: recalibration of the body schema; violation of the body schema; multisensory integration; and illusory experience over time. The report of agency was a significant predictor of proprioceptive distortion. This study shows how first-person methodologies
can be empirically rigorous and how the introspective interview provides a rich, detailed account of embodied experience.
KeywordsAgency-Body schema-Embodiment-Interpretative phenomenological analysis-Proprioceptive drift-Rubber hand illusion
Most people are convinced that their body parts are in fact their own, but in some clinical conditions, this sense of ownership can be lost [1]. Perceptual illusions, most famously the rubber hand illusion (RHI) [2], demonstrate that a sense of ownership over a body part (or an entire body [3]) that is not in fact ours can be easily induced in healthy volunteers. But does illusory ownership over an artificial body part have consequences for the real body part, the one that has been 'replaced'? Recent data show the RHI induces a small but robust drop in skin temperature of the real hand. That is, blood flow to the 'disowned' hand seems to be selectively reduced [1]. Such a finding is particularly relevant to the immune system because a primary role of the immune system is to 'discriminate self from non-self'[4]. We predicted that the innate immune system may be upregulated in a manner consistent with rejection of the replaced hand. Consistent with this prediction, we report here that the RHI increases histamine reactivity, which is a key final pathway of the innate immune response and has been implicated in autoimmune disorders, including multiple sclerosis [5]. Our finding has direct implications for autoimmune disorders and a range of neurological and psychiatric conditions characterised by a disrupted sense of ownership over one's body (see [1] for a list of conditions), and has broader implications that extend well beyond previous assertions about the mind-body link.
Within the past few decades, there has been a surge of interest in the investigation of mindfulness as a psychological construct and as a form of clinical intervention. This article reviews the empirical literature on the effects of mindfulness on psychological health. We begin with a discussion of the construct of mindfulness, differences between Buddhist and Western psychological conceptualizations of mindfulness, and how mindfulness has been integrated into Western medicine and psychology, before reviewing three areas of empirical research: cross-sectional, correlational research on the associations between mindfulness and various indicators of psychological health; intervention research on the effects of mindfulness-oriented interventions on psychological health; and laboratory-based, experimental research on the immediate effects of mindfulness inductions on emotional and behavioral functioning. We conclude that mindfulness brings about various positive psychological effects, including increased subjective well-being, reduced psychological symptoms and emotional reactivity, and improved behavioral regulation. The review ends with a discussion on mechanisms of change of mindfulness interventions and suggested directions for future research.
Depersonalization is characterised by a profound disruption of self-awareness mainly characterised by feelings of disembodiment and subjective emotional numbing. It has been proposed that depersonalization is caused by a fronto-limbic (particularly anterior insula) suppressive mechanism--presumably mediated via attention--which manifests subjectively as emotional numbing, and disables the process by which perception and cognition normally become emotionally coloured, giving rise to a subjective feeling of 'unreality'. Our functional neuroimaging and psychophysiological studies support the above model and indicate that, compared with normal and clinical controls, DPD patients show increased prefrontal activation as well as reduced activation in insula/limbic-related areas to aversive, arousing emotional stimuli. Although a putative inhibitory mechanism on emotional processing might account for the emotional numbing and characteristic perceptual detachment, it is likely, as suggested by some studies, that parietal mechanisms underpin feelings of disembodiment and lack of agency feelings.
This is the first clinical trial of repetitive Transcranial Magnetic Stimulation (rTMS) in depersonalization disorder (DPD). After 3weeks of right temporo-parietal junction (TPJ) rTMS, 6/12 patients responded. Five responders received 3 more weeks of right TPJ rTMS showing 68% DPD symptoms improvement. Right TPJ rTMS was safe and effective.
Human neuropsychology suggests that there are two distinct body representations. Body image and body schema are, respectively, thought to be involved in conscious perceptual judgments and unconscious sensorimotor guidance. The evidence is based on the double dissociation between disorders of perceptual detection and sensorimotor guidance. Until now, research focused on cases that had impaired tactile pressure sensitivity and comparisons of performance were of cases suffering from different types of lesions (peripheral and central). Here, we report a unique double dissociation in two stroke patients with intact basic somatosensory processing (tactile detection). One patient was poor at identifying the position of where she had been touched on a line drawing of a hand, but was able to point accurately towards the actual position on her/his hand itself. The reverse pattern was observed in the other patient. This finding provides further support for separate processing for body image and body scheme.
The sense of body ownership represents a fundamental aspect of our self-awareness, but is disrupted in many neurological, psychiatric, and psychological conditions that are also characterized by disruption of skin temperature regulation, sometimes in a single limb. We hypothesized that skin temperature in a specific limb could be disrupted by psychologically disrupting the sense of ownership of that limb. In six separate experiments, and by using an established protocol to induce the rubber hand illusion, we demonstrate that skin temperature of the real hand decreases when we take ownership of an artificial counterpart. The decrease in skin temperature is limb-specific: it does not occur in the unstimulated hand, nor in the ipsilateral foot. The effect is not evoked by tactile or visual input per se, nor by simultaneous tactile and visual input per se, nor by a shift in attention toward the experimental side or limb. In fact, taking ownership of an artificial hand slows tactile processing of information from the real hand, which is also observed in patients who demonstrate body disownership after stroke. These findings of psychologically induced limb-specific disruption of temperature regulation provide the first evidence that: taking ownership of an artificial body part has consequences for the real body part; that the awareness of our physical self and the physiological regulation of self are closely linked in a top-down manner; and that cognitive processes that disrupt the sense of body ownership may in turn disrupt temperature regulation in numerous states characterized by both.
• body image
• consciousness
• crossmodal integration
• homeostasis
The functional properties of neurons located in the rostral part of inferior area 6 were studied in awake, partially restrained macaque monkeys. The most interesting property of these neurons was that their firing correlated with specific goal-related motor acts rather than with single movements made by the animal. Using the motor acts as the classification criterion we subdivided the neurons into six classes, four related to distal motor acts and two related to proximal motor acts. The distal classes are: "Grasping-with-the-hand-and-the-mouth neurons", "Grasping-with-the-hand neurons", "Holding neurons" and "Tearing neurons". The proximal classes are: "Reaching neurons" and "Bringing-to-the-mouth-or-to-the-body neurons". The vast majority of the cells belonged to the distal classes. A particularly interesting aspect of distal class neurons was that the discharge of many of them depended on the way in which the hand was shaped during the motor act. Three main groups of neurons were distinguished: "Precision grip neurons", "Finger prehension neurons", "Whole hand prehension neurons". Almost the totality of neurons fired during motor acts performed with either hand. About 50% of the recorded neurons responded to somatosensory stimuli and about 20% to visual stimuli. Visual neurons were more difficult to trigger than the corresponding neurons located in the caudal part of inferior area 6 (area F4). They required motivationally meaningful stimuli and for some of them the size of the stimulus was also critical. In the case of distal neurons there was a relationship between the type of prehension coded by the cells and the size of the stimulus effective in triggering the neurons. It is proposed that the different classes of neurons form a vocabulary of motor acts and that this vocabulary can be assessed by somatosensory and visual stimuli.
One hypothesis concerning the human dorsal anterior cingulate cortex (ACC) is that it functions, in part, to signal the occurrence of conflicts in information processing, thereby triggering compensatory adjustments in cognitive control. Since this idea was first proposed, a great deal of relevant empirical evidence has accrued. This evidence has largely corroborated the conflict-monitoring hypothesis, and some very recent work has provided striking new support for the theory. At the same time, other findings have posed specific challenges, especially concerning the way the theory addresses the processing of errors. Recent research has also begun to shed light on the larger function of the ACC, suggesting some new possibilities concerning how conflict monitoring might fit into the cingulate's overall role in cognition and action.
Prior findings of emotional numbness (rather than distress) among socially excluded persons led the authors to investigate whether exclusion causes a far-reaching insensitivity to both physical and emotional pain. Experiments 1-4 showed that receiving an ostensibly diagnostic forecast of a lonesome future life reduced sensitivity to physical pain, as indicated by both (higher) thresholds and tolerance. Exclusion also caused emotional insensitivity, as indicated by reductions in affective forecasting of joy or woe over a future football outcome (Experiment 3), as well as lesser empathizing with another person's suffering from either romantic breakup (Experiment 4) or a broken leg (Experiment 5). The insensitivities to pain and emotion were highly intercorrelated.
In this study, the spatial limits of referred touch to a rubber hand were investigated. Participants rated the strength of the perceived illusion when the rubber hand was placed in one of six different spatial positions (at a distance of 17.5-67.5cm horizontal from the participant's own hand). The results revealed a significant nonlinear relationship in the strength of the illusion, with the strongest ratings given when the two hands were closest; decaying significantly after a distance of 30cm. The time taken to elicit the illusion followed a similar trend. These results may reflect the response properties of bimodal visuo-tactile cells encoding peripersonal space around the hand.
What is it like to have a body? The present study takes a psychometric approach to this question. We collected structured introspective reports of the rubber hand illusion, to systematically investigate the structure of bodily self-consciousness. Participants observed a rubber hand that was stroked either synchronously or asynchronously with their own hand and then made proprioceptive judgments of the location of their own hand and used Likert scales to rate their agreement or disagreement with 27 statements relating to their subjective experience of the illusion. Principal components analysis of this data revealed four major components of the experience across conditions, which we interpret as: embodiment of rubber hand, loss of own hand, movement, and affect. In the asynchronous condition, an additional fifth component, deafference, was found. Secondary analysis of the embodiment of runner hand component revealed three subcomponents in both conditions: ownership, location, and agency. The ownership and location components were independent significant predictors of proprioceptive biases induced by the illusion. These results suggest that psychometric tools may provide a rich method for studying the structure of conscious experience, and point the way towards an empirically rigorous phenomenology.
The present study examined how acute dissociation, trait-like dissociative symptoms, and physiological reactivity relate to each other. Sixty-nine undergraduate students were exposed to 14 aversive auditory probes, while their skin conductance responses were measured. A combination of self-reported anxiety and trait-like dissociation was found to predict variability in peritraumatic dissociation levels induced by the aversive probes. Furthermore, high levels of acute dissociation were associated with faster habituation of skin conductance responding, while trait-like dissociation was unrelated to habituation. Interestingly, individuals who reported childhood trauma displayed elevated skin conductance responses. Our findings contribute to the growing body of evidence indicating that subjective feelings of acute dissociation have their objective concomitants, notably fast habituation of physiologic responses.
Tanulás, vizuális poszturális testmodell és a tudat kialakulása
- Marton L. M.