Aikaterini Fotopoulou

Hands only illusion: multisensory integration elicits sense of ownership for body parts but not for non-corporeal objects

Abstract The experience of body ownership can be successfully manipulated during the rubber hand illusion using synchronous multisensory stimulation. The hypothesis that multisensory integration is both a necessary and sufficient condition for body ownership is debated. We systematically varied the appearance of the object that was stimulated in synchrony or asynchrony with the participant’s hand. A viewed object that was transformed in three stages from a plain wooden block to a wooden hand was compared to a realistic rubber hand. Introspective and behavioural results show that participants experience a sense of ownership only for the realistic prosthetic hand, suggesting that not all objects can be experienced as part of one’s body. Instead, the viewed object must fit with a reference model of the body that contains important structural information about body parts. This body model can distinguish between corporeal and non-corporeal objects, and it therefore plays a critical role in maintaining a coherent sense of one’s body.

The role of motor intention in motor awareness: an experimental study on anosognosia for hemiplegia

Recent theories propose that anosognosia for hemiplegia (AHP) results from specific impairments in motor planning. However, no study has hitherto directly investigated the role of motor intention in the observed non-veridical awareness of action in AHP. We developed the following paradigm to investigate the role of motor planning in awareness in patients with AHP: Four hemiplegic patients with and four without anosognosia were provided with false visual feedback of movement in their left paralysed arm through a prosthetic rubber hand. We examined whether the ability to detect presence or absence of movement based on visual evidence varied according to whether the patient had planned to move their limb or not. Motor intention had a selective effect on patients with AHP; they were more likely than controls (U = 16, P < 0.001) to ignore the visual feedback of a motionless hand and claim that they moved it when they had the intention to do so (self-generated movement) than when they expected an experimenter to move their own hand (externally generated movement), or there was no expectation of movement. By contrast, patients without AHP were not influenced by these manipulations, and did not claim they moved their hand when the hand remained still. This is the first direct demonstration that altered awareness of action in AHP reflects a dominance of motor intention prior to action over sensory information about the actual effects of movement.

The Social Modulation of Pain: Others as Predictive Signals of Salience – a Systematic Review

Several studies in cognitive neuroscience have investigated the cognitive and affective modulation of pain. By contrast, fewer studies have focused on the social modulation of pain, despite a plethora of relevant clinical findings. Here we present the first review of experimental studies addressing how interpersonal factors, such as the presence, behavior, and spatial proximity of an observer, modulate pain. Based on a systematic literature search, we identified 26 studies on experimentally induced pain that manipulated different interpersonal variables and measured behavioral, physiological, and neural pain-related responses. We observed that the modulation of pain by interpersonal factors depended on (1) the degree to which the social partners were active or were perceived by the participants to possess possibility for action; (2) the degree to which participants could perceive the specific intentions of the social partners; (3) the type of pre-existing relationship between the social partner and the person in pain, and lastly, (4) individual differences in relating to others and coping styles. Based on these findings, we propose that the modulation of pain by social factors can be fruitfully understood in relation to a recent predictive coding model, the free energy framework, particularly as applied to interoception and social cognition. Specifically, we argue that interpersonal interactions during pain may function as social, predictive signals of contextual threat or safety and as such influence the salience of noxious stimuli. The perception of such interpersonal interactions may in turn depend on (a) prior beliefs about interpersonal relating and (b) the certainty or precision by which an interpersonal interaction may predict environmental threat or safety.

Confabulation: Motivated reality monitoring

The study addressed the hypothesis that the content of confabulation is emotionally biased. Confabulating amnesic patients were compared with amnesic non-confabulating patients in a memory recognition experiment that manipulated the valence (pleasant, unpleasant), temporal source (past, present, future) and selection agent (self, other) of the to-be-recognised memories. The results revealed that confabulating patients were more likely than amnesic non-confabulating patients to incorrectly recognise past autobiographical events or thoughts as currently relevant memories, and this was more pronounced for pleasant compared to unpleasant events. These findings suggest that motivational factors, along with defective reality and temporality monitoring, contribute to confabulation.

The affective neuropsychology of confabulation and delusion

The paper reviews the history of the scientific understanding of the role of emotion in confabulation and delusion. I argue that the significance of emotion in the pathogenesis of these symptoms was obscured by academic polarisation between psychodynamic and neurocognitive traditions and was also often obfuscated by rigid distinctions between psychogenic and neurogenic explanations. This tradition of epistemic dualism was implicitly maintained in the fields of cognitive neuropsychology and cognitive neuropsychiatry. This paper focuses on memory-related confabulation following ventromedial frontal lobe lesions, awareness-related confabulation following right perisylvian lesions, and delusions of various aetiologies. Ambiguity regarding the definition and taxonomy of symptoms renders direct comparison difficult, but certain overriding principles are becoming discernible. Recent findings suggest that emotion and motivation influence both confabulation and delusion. These influences may be instigated directly by neural dysfunction or indirectly by life changes and altered social circumstances, or by a combination of these. Importantly, the rejection of epistemic dualism in the conceptualisation of both symptoms can allow us to study them in parallel and draw conclusions about the relation between cognition and emotion. Specifically, confabulation and delusion can be described as faulty attempts to balance the conflicting demands of accurate and self-serving reality representation.

A Spatiotemporal Profile of In Vivo Cerebral Blood Flow Changes Following Intranasal Oxytocin in Humans

BACKGROUND Animal and human studies highlight the role of oxytocin in social cognition and behavior and the potential of intranasal oxytocin (IN-OT) to treat social impairment in individuals with neuropsychiatric disorders such as autism. However, extensive efforts to evaluate the central actions and therapeutic efficacy of IN-OT may be marred by the absence of data regarding its temporal dynamics and sites of action in the living human brain. METHODS In a placebo-controlled study, we used arterial spin labeling to measure IN-OT-induced changes in resting regional cerebral blood flow (rCBF) in 32 healthy men. Volunteers were blinded regarding the nature of the compound they received. The rCBF data were acquired 15 min before and up to 78 min after onset of treatment onset (40 IU of IN-OT or placebo). The data were analyzed using mass univariate and multivariate pattern recognition techniques. RESULTS We obtained robust evidence delineating an oxytocinergic network comprising regions expected to express oxytocin receptors, based on histologic evidence, and including core regions of the brain circuitry underpinning social cognition and emotion processing. Pattern recognition on rCBF maps indicated that IN-OT-induced changes were sustained over the entire posttreatment observation interval (25-78 min) and consistent with a pharmacodynamic profile showing a peak response at 39-51 min. CONCLUSIONS Our study provides the first visualization and quantification of IN-OT-induced changes in rCBF in the living human brain unaffected by cognitive, affective, or social manipulations. Our findings can inform theoretical and mechanistic models regarding IN-OT effects on typical and atypical social behavior and guide future experiments (e.g., regarding the timing of experimental manipulations).

Anosognosia for Motor Impairment Following Left Brain Damage

Anosognosia for motor impairment has been linked to lesions of the right hemisphere. However, left hemisphere damaged patients have often been excluded from investigation because of their associated language deficits. In this study we assessed anosognosia for motor disorders in a group of left hemisphere damaged patients using 2 tools that assess the presence of unawareness—a structured interview that is a common method of assessment of anosognosia in clinical settings, and a new tool, the Visual-Analogue Test for Anosognosia for Motor Impairment (VATAm; Della Sala, Cocchini, Beschin, & Cameron, in press). The structured interview relies heavily on language and enquires about general motor ability whereas the VATAm is less dependent on language abilities and enquires about specific motor tasks. Results suggest that the frequency of anosognosia in left brain damaged patients may have been underestimated due to methodological reasons, and that anosognosia for motor impairment can also be associated with lesions of the left hemisphere.

False selves in neuropsychological rehabilitation: The challenge of confabulation

The presence of confabulation following brain damage can obstruct neuropsychological rehabilitation and management. A recent theoretical approach to confabulation emphasises that neurocognitive deficits are not sufficient to account for the content of confabulation. As a result, they are also insufficient to address the unique rehabilitation challenges that confabulation raises. Instead, confabulation could be best understood as the magnification of existing reconstructive memory processes, influenced by both neurocognitive and motivational factors. The paper reviews recent experimental findings showing that confabulations serve important functions of self-coherence and self-enhancement, despite their poor correspondence to reality. Case material is used to illustrate the meaningfulness of confabulation from the subjective perspective of the patient and to demonstrate that such a theoretical approach to confabulation can best inform management and rehabilitation efforts.

Knowing you care: Effects of perceived empathy and attachment style on pain perception

&NA; Other people can have a significant impact on ones pain. Although correlational data abound, causal relationships between ones pain experience, individual traits of social relating (e.g. attachment style), and social factors (e.g. empathy) have not been investigated. Here, we studied whether the presence of others and ‘perceived empathy’ (defined as participants’ knowledge of the extent to which observers felt they understood and shared their pain) can modulate subjective and autonomic responses to pain; and whether these influences can be explained by individual traits of pain coping and social attachment. Participants received noxious thermal stimuli via a thermode attached to their forearm and were asked to rate their pain. In separate blocks they were witnessed by (a) high‐empathic and (b) low‐empathic unfamiliar observers, and in a third condition (c) no observer was present (alone condition). We found that the effects of social presence and empathy on pain ratings depended on individual differences in attachment style. Higher scores on attachment anxiety predicted higher pain ratings in the low‐empathy than in the high‐empathy condition; and higher scores on attachment avoidance predicted lower pain ratings in the alone condition than with social presence. In addition, social presence decreased autonomic responses to pain irrespective of individual personality traits. To our knowledge this is the first time that adult attachment style has been shown to modulate the effects of social presence and ‘perceived empathy’ on experimentally induced pain. The results are discussed in relation to recent cognitive models of pain coping and attachment theory.

Bodily pleasure matters: velocity of touch modulates body ownership during the rubber hand illusion

The sense of body ownership represents a fundamental aspect of our self-consciousness. Influential experimental paradigms, such as the rubber hand illusion (RHI), in which a seen rubber hand is experienced as part of ones body when ones own unseen hand receives congruent tactile stimulation, have extensively examined the role of exteroceptive, multisensory integration on body ownership. However, remarkably, despite the more general current interest in the nature and role of interoception in emotion and consciousness, no study has investigated how the illusion may be affected by interoceptive bodily signals, such as affective touch. Here, we recruited 52 healthy, adult participants and we investigated for the first time, whether applying slow velocity, light tactile stimuli, known to elicit interoceptive feelings of pleasantness, would influence the illusion more than faster, emotionally-neutral, tactile stimuli. We also examined whether seeing another persons hand vs. a rubber hand would reduce the illusion in slow vs. fast stroking conditions, as interoceptive signals are used to represent ones own body from within and it is unclear how they would be integrated with visual signals from another persons hand. We found that slow velocity touch was perceived as more pleasant and it produced higher levels of subjective embodiment during the RHI compared with fast touch. Moreover, this effect applied irrespective of whether the seen hand was a rubber or a confederates hand. These findings provide support for the idea that affective touch, and more generally interoception, may have a unique contribution to the sense of body ownership, and by implication to our embodied psychological “self.”