ASSESSING THE EMOTIONAL DIMENSIONS OF THE CUTANEOUS-RABBIT EFFECT USING FACES

This research investigated how emotional images affects tactile saltation. More specifically, we combined visual faces with three different emotions: angry, sad and happy with a tactile illusion known as the cutaneous rabbit effect (CRE) that was delivered on participants’ shoulder at different durations. Because some of the faces were political figures, we assessed participant’s political affiliation using Political Typology Quiz. Participants rated their emotional response using the self-assessment manikin (SAM), a three dimensional scale that measures valence, arousal and dominance. For the valence dimension, our results indicate that participants found it less pleasant to see likeable faces sad than any other figure. Data also showed that it was the least pleasant for participants to see a hateful public face when they were angry. Political affiliation and the duration of the CRE both affected the arousal dimension suggesting that liberals seems more concerned by fictional and public figures than political ones while conservatives seems to be more affected by angry faces of political figures when the tactile duration is the longest. Finally, for the dominance dimension, it was found that likeable figures made participants feel more in control of the situation and that dislikeable figures made participants feel controlled

Effects of Visual Locomotion and Tactile Stimuli Duration on the Emotional Dimensions of the Cutaneous Rabbit Illusion

In this study, we assessed the emotional dimensions (valence, arousal, and dominance) of the multimodal visual-cutaneous rabbit effect. Simultaneously to the tactile bursts on the forearm, visual silhouettes of saltatorial animals (rabbit, kangaroo, spider, grasshopper, frog, and flea) were projected on the left arm. Additionally, there were two locomotion conditions: taking-off and landing. The results showed that the valence dimension (happy-unhappy) was only affected by the visual stimuli with no effect of the tactile conditions nor the locomotion phases. Arousal (excited-calm) showed a significant difference for the three tactile conditions with an interaction effect with the locomotion condition. Arousal scores were higher when the taking-off condition was associated with the intermediate duration (24 ms) and when the landing condition was associated with either the shortest duration (12 ms) or the longest duration (48 ms). There was no effect for the dominance dimension. Similar to our previous results, the valence dimension seems to be highly affected by visual information reducing any effect of tactile information, while touch can modulate the arousal dimension. This can be beneficial for designing multimodal interfaces for virtual or augmented reality.acceptedVersionPeer reviewe

Touching is believing: creating illusions and feeling of embodiment with mid-air haptic technology

Over the last two decades, the sense of touch has received new attention from the scientific community.Several haptic devices have been developed to address the complexity of the sense of touch, the latest addition being mid-air (contactless) haptic technology. An interesting series of previous research has suggested an easier way to tackle the complexity of designing convincing tactile sensations by exploiting tactile illusions. Tactile illusions rely on perceptual shortcuts based on the psychophysics of the tactile receptors. Currently, studies exploring the perceptual space of mid-air haptics and its applicability in the tactile illusions field are still limited in number. This thesis aims to contribute to the field of Human-Computer Interaction (HCI) by investigating the perceptual design space of ultrasonic mid-air haptics technology. Specifically, in a first set of three studies, we investigate the absolute thresholds (minimal amount of a property of astimulus that a user can detect) for control points (CP) at different frequencies on the hand and arm (Study 1). Then we investigate the optimal sampling rate needed to drive the device in an optimal fashion and its relationship with shape size (Study 2). Next, we apply a new technique to increase users’ performance in a shape discrimination task (Study 3). In Study 4, we start the exploration of a tactile illusion of movement using contact touch and later, we apply a similar procedure to investigate the feasibility of creating a tactile illusion of movement between the two non-interconnected hands by using mid-air touch (Study 5). Finally, in Study 6, we explore our sense of touch in VR, while providing an illusion of rain drops through mid-air haptics, to recreate a virtual hand illusion (VHI) to explore the boundaries of our sense of embodiment. Therefore, the contribution of this work is threefold: a) we contribute by adding new knowledge on the psychophysical space for mid-air haptics, b) we test the potential to create realistic tactile sensations by exploiting tactile illusions with mid-air haptic technology, and c) we demonstrate how tactile illusions mediated by mid-air haptics can convey a sense of embodiment in VR environments

Visual-somatosensory interactions in mental representations of the body and the face

The body is represented in the brain at levels that incorporate multisensory information. This thesis focused on interactions between vision and cutaneous sensations (i.e., touch and pain). Experiment 1 revealed that there are partially dissociable pathways for visual enhancement of touch (VET) depending upon whether one sees one’s own body or the body of another person. This indicates that VET, a seeming low-level effect on spatial tactile acuity, is actually sensitive to body identity. Experiments 2-4 explored the effect of viewing one’s own body on pain perception. They demonstrated that viewing the body biases pain intensity judgments irrespective of actual stimulus intensity, and, more importantly, reduces the discriminative capacities of the nociceptive pathway encoding noxious stimulus intensity. The latter effect only occurs if the pain-inducing event itself is not visible, suggesting that viewing the body alone and viewing a stimulus event on the body have distinct effects on cutaneous sensations. Experiment 5 replicated an enhancement of visual remapping of touch (VRT) when viewing fearful human faces being touched, and further demonstrated that VRT does not occur for observed touch on non-human faces, even fearful ones. This suggests that the facial expressions of non-human animals may not be simulated within the somatosensory system of the human observer in the same way that the facial expressions of other humans are. Finally, Experiment 6 examined the enfacement illusion, in which synchronous visuo-tactile inputs cause another’s face to be assimilated into the mental self-face representation. The strength of enfacement was not affected by the other’s facial expression, supporting an asymmetric relationship between processing of facial identity and facial expressions. Together, these studies indicate that multisensory representations of the body in the brain link low-level perceptual processes with the perception of emotional cues and body/face identity, and interact in complex ways depending upon contextual factors

Somatic ABC's: A Theoretical Framework for Designing, Developing and Evaluating the Building Blocks of Touch-Based Information Delivery

abstract: Situations of sensory overload are steadily becoming more frequent as the ubiquity of technology approaches reality--particularly with the advent of socio-communicative smartphone applications, and pervasive, high speed wireless networks. Although the ease of accessing information has improved our communication effectiveness and efficiency, our visual and auditory modalities--those modalities that today's computerized devices and displays largely engage--have become overloaded, creating possibilities for distractions, delays and high cognitive load; which in turn can lead to a loss of situational awareness, increasing chances for life threatening situations such as texting while driving. Surprisingly, alternative modalities for information delivery have seen little exploration. Touch, in particular, is a promising candidate given that it is our largest sensory organ with impressive spatial and temporal acuity. Although some approaches have been proposed for touch-based information delivery, they are not without limitations including high learning curves, limited applicability and/or limited expression. This is largely due to the lack of a versatile, comprehensive design theory--specifically, a theory that addresses the design of touch-based building blocks for expandable, efficient, rich and robust touch languages that are easy to learn and use. Moreover, beyond design, there is a lack of implementation and evaluation theories for such languages. To overcome these limitations, a unified, theoretical framework, inspired by natural, spoken language, is proposed called Somatic ABC's for Articulating (designing), Building (developing) and Confirming (evaluating) touch-based languages. To evaluate the usefulness of Somatic ABC's, its design, implementation and evaluation theories were applied to create communication languages for two very unique application areas: audio described movies and motor learning. These applications were chosen as they presented opportunities for complementing communication by offloading information, typically conveyed visually and/or aurally, to the skin. For both studies, it was found that Somatic ABC's aided the design, development and evaluation of rich somatic languages with distinct and natural communication units.Dissertation/ThesisPh.D. Computer Science 201

Haptics: Science, Technology, Applications

This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications

The roles of the somatosensory cortices in the perception of noxious and innocuous stimuli

Résumé Les premières études électrophysiologiques et anatomiques ont établi le rôle crucial du cortex somatosensoriel primaire et secondaire (SI et SII) dans le traitement de l'information somatosensorielle. Toutefois, les récentes avancées en techniques d’imagerie cérébrale ont mis en question leur rôle dans la perception somatosensorielle. La réorganisation du cortex somatosensoriel est un phénomène qui a été proposé comme cause de la douleur du membre fantôme chez les individus amputés. Comme la plupart des études se sont concentrées sur le rôle du SI, une étude plus approfondie est nécessaire. La présente série d'expériences implique une exploration du rôle des régions somatosensorielles dans la perception des stimuli douleureux et non-douleureux chez des volontaires sains et patients avec des douleurs de membre fantôme. La première étude expérimentale présentée dans le chapitre 3 est une méta-analyse des études de neuro-imagerie employant des stimuli nociceptifs chez des volontaires sains. En comparaison aux précédentes, la présente étude permet la génération de cartes quantitatives probabilistes permettant la localisation des régions activées en réponse à des stimuli nociceptifs. Le rôle du cortex somatosensoriel dans la perception consciente de stimuli chauds a été étudié dans le chapitre 4 grâce à une étude d'imagerie par résonance magnétique fonctionnelle, dans laquelle des stimuli thermiques douloureux et non-douloureux ont été administrés de manière contrebalancée. Grâce à cette procédure, la perception de la chaleur fut atténuée par les stimuli douloureux, ce qui permit la comparaison des stimuli consciemment perçus avec ceux qui ne le furent pas. Les résultats ont montrés que les stimulations chaudes perçues ont engendré l’activation de l’aire SI controlatérale, ainsi que de la région SII. Grâce à l’évaluation clinique de patients amputés présentant une altération de leurs perceptions somatosensorielles, il est également possible de dessiner un aperçu des régions corticales qui sous-tendent ces modifications perceptuelles. Dans le chapitre 5 nous avons émis l'hypothèse proposant que les sensations du membre fantôme représentent un corrélat perceptuel de la réorganisation somatotopique des représentations sensorielles corticales. En effet, la réorganisation des sensations peut donner des indices sur les régions impliquées dans la genèse des sensations référées. Ainsi, un protocole d’évaluation sensoriel a été administré à un groupe de patients affligés de douleur au niveau du membre fantôme. Les résultats ont montré que, contrairement aux études précédentes, les sensations diffèrent grandement selon le type et l'intensité des stimuli tactiles, sans évidence de la présence d’un modèle spatialement localisé. Toutefois, les résultats actuels suggèrent que les régions corticales à champs récepteurs bilatéraux présentent également des modifications en réponse à une déafférentation. Ces études présentent une nouvelle image des régions corticales impliquées dans la perception des stimuli somatosensoriels, lesquelles comprennent les aires SI et SII, ainsi que l'insula. Les résultats sont pertinents à notre compréhension des corrélats neurologiques de la perception somatosensorielle consciente.Abstract Early anatomical and single-unit recording studies established a crucial role for the primary and secondary somatosensory cortices (SI & SII) in processing somatosensory information. However, recent advances in brain imaging and analysis techniques have called into question their role in somatosensation. Findings from this recent research are relevant to the study of the reorganizational changes occurring in the somatosensory cortices that have been causally linked to the genesis of pain in amputee patients. These patients continue to perceive and experience pain in the absent limb, which is usually referred to as phantom-limb pain; but little research on this phenomenon has focused on other regions outside SI, and further study is needed. The present series of experiments involve an exploration of the roles of the somatosensory cortices in the perception of noxious and innocuous tactile stimuli in healthy volunteers and patients with phantom-limb pain. The first experimental study in Chapter 3 is a meta-analytic review of neuroimaging studies examining noxious stimuli evoked activation in healthy volunteers. In comparison to previous reviews that have merely reported the prevalence of pain-related activation, the present study yields quantitative probabilistic maps that permit localization of the likelihood of obtaining activation in response to noxious stimuli within any brain region. The role of the somatosensory cortices in the conscious perception of brief warm stimuli was explored in Chapter 4 using functional magnetic resonance imaging, where noxious and innocuous thermal stimuli were counterbalanced within the experimental protocol. This procedure allowed a gating of the somatosensory system in which the perception of warm stimuli was attenuated by painful stimuli, thus permitting the comparison of detected with undetected stimuli. Results showed that detected warm stimuli significantly activated SI and SII. It is also possible to draw insight regarding which cortical regions subserve somatosensory processing and its organization by clinical assessment of amputee patients, who demonstrate altered somatosensation. To date, few studies have explored the relationship between referred sensations to the phantom and cortical reorganization. In Chapter 5 we hypothesized that referred sensations to phantom limbs are a perceptual correlates of a somatotopic reorganization of sensory representations. Derangements in referred sensations can give clues to the regions involved in referred sensations genesis. Thus, a quantitative sensory testing protocol was administered to a group of phantom-limb pain patients. Results showed that, contrary to previous reports, referred sensations to the phantom differed greatly based on the type and intensity of the tactile stimuli applied to the body, with no evidence of a spatially localized pattern. Previous reports of referred sensations have solely focused on plastic changes in SI. However, the present results suggest that other cortical regions with bilateral receptive fields also undergo reorganizational changes in response to deafferentation. These studies present an emerging picture of the cortical regions involved in the perception of somatosensory stimuli, which include SI and SII, as well as the insula. Findings are relevant to our understanding of the neural correlates of conscious perception of somatosensation and the formation of the mental representation of stimuli applied to the body

Somaesthesia, autonomic dysfunction and the perception of pain in complex regional pain syndrome and chronic rheumatic disease

The perception of pain is a complex process involving central integration of nociceptive sensory signals with autonomic, emotional, motor and behavioural cortical networks. The principal aim of this thesis was to explore how this process contributes to the presenting clinical phenotype in complex regional pain syndrome (CRPS), and whether this extends to other chronic pain conditions in rheumatic disease such as osteoarthritis (OA) and rheumatoid arthrits (RA). The first study established baseline quantitative sensory testing parameters and autonomic function. It found that allodynia was absent in controls, present in some OA and RA patients and most marked in CRPS patients. Autonomic function was normal in controls, with some impairment in OA and RA and most dysfunction in CRPS. The second study used an optokinetic visuo-motor challenge induced by a mirror-whiteboard device. The presence or absence of sensory disturbances and/or new/worsening pain was used to generate a vulnerability scale. Controls were the least vulnerable followed by RA, then OA with CRPS the most vulnerable. Autonomic responses, sensory disturbances and new/worsening pain to a pure visual conflict in the form of ambiguous visual stimuli (AVS) were used for the third study. Sensory disturbances, pain enhancement and abnormal asymmetric autonomic responses occurred only in the CRPS cohort. The final study investigated parietal lobe function in CRPS patients. It showed clinical evidence of parietal lobe dysfunction present in a substantial number of CRPS patients, and that this was reflected both in symptoms and impact upon activities of daily living. Overall, the thesis findings support the concept that perterbation of central somaesthetic integration may induce cortical network dysfunction, reflected in different patterns of autonomic and pain responses. This might contribute to the differing clinical presentations seen in CRPS. Similar processes may also occur in OA and RA. This work provides an approach to the clinical phenotyping of CRPS and other chronic painful rheumatic diseases. Appreciation of the potential mechanisms described may allow better targeting of therapy.EThOS - Electronic Theses Online ServiceGBUnited Kingdo