Sensorimotor Induction of Auditory Misattribution in Early Psychosis.

Dysfunction of sensorimotor predictive processing is thought to underlie abnormalities in self-monitoring producing passivity symptoms in psychosis. Experimentally induced sensorimotor conflict can produce a failure in bodily self-monitoring (presence hallucination [PH]), yet it is unclear how this is related to auditory self-monitoring and psychosis symptoms. Here we show that the induction of sensorimotor conflict in early psychosis patients induces PH and impacts auditory-verbal self-monitoring. Participants manipulated a haptic robotic system inducing a bodily sensorimotor conflict. In experiment 1, the PH was measured. In experiment 2, an auditory-verbal self-monitoring task was performed during the conflict. Fifty-one participants (31 early psychosis patients, 20 matched controls) participated in the experiments. The PH was present in all participants. Psychosis patients with passivity experiences (PE+) had reduced accuracy in auditory-verbal self-other discrimination during sensorimotor stimulation, but only when sensorimotor stimulation involved a spatiotemporal conflict (F(2, 44) = 6.68, P = .002). These results show a strong link between robotically controlled alterations in sensorimotor processing and auditory misattribution in psychosis and provide evidence for the role of sensorimotor processes in altered self-monitoring in psychosis

Multisensory and sensorimotor origins of the sense of self

Cognitive neuroscience has increasingly focused on studying the subject, i.e. the self, of conscious experience. In order to be the subject of an experience, we generally experience owning a physical body, being located within that body, and being able to distinguish the body and its actions from others. These pre-reflective experiences are based on brain mechanisms of multisensory and sensorimotor integration. In this thesis I investigated how our sense of self, in particular the senses of body ownership and of agency, depend on multimodal bodily signals. I achieved this by using approaches developed by cognitive neuroscience to study how the sense of self relates to the processing of bodily signals: creating bodily illusions with multisensory conflicts through the use of virtual reality and robotics. The first part of this thesis describes the investigation of the sense of body ownership in healthy subjects and in spinal cord injury patients, achieved by inducing conflicts between tactile information and visual feedback. The research presented in the second part of the thesis is centered on the experience of self-touch. There, I have first investigated how the manipulation of reference frames influences the perception of the illusion of self-touch, and second, how active self-touch influences the sense of body ownership. Lastly, in the third part of the thesis, I investigated how experimentally induced multisensory and sensorimotor conflicts perturb the sense of self in healthy subjects and induce experiences similar to certain symptoms observed in neurological and psychiatric disorders. I show that particular conflicts between bodily signals not only affect body perception and sense of agency for motor actions but also propagate to higher levels and influence even the sense of agency for mental representations in healthy subjects. Finally, I discuss my results and their relation to existing knowledge on bodily self-consciousness and position them in a broader picture of our current understanding of the self

Voluntary self-touch increases body ownership

Experimental manipulations of body ownership have indicated that multisensory integration is central to forming bodily self representation. Voluntary self touch is a unique multisensory situation involving corresponding motor, tactile and proprioceptive signals. Yet, even though self-touch is frequent in everyday life, its contribution to the formation of body ownership is not well understood. Here we investigated the role of voluntary self touch in body ownership using a novel adaptation of the rubber hand illusion (RHI), in which a robotic system and virtual reality allowed participants self-touch of real and virtual hands. In the first experiment, active and passive self-touch were applied in the absence of visual feedback. In the second experiment, we tested the role of visual feedback in this bodily illusion. Finally, in the third experiment, we compared active and passive self-touch to the classical RHI in which the touch is administered by the experimenter. We hypothesized that active self-touch would increase ownership over the virtual hand through the addition of motor signals strengthening the bodily illusion. The results indicated that active self-touch elicited stronger illusory ownership compared to passive self-touch and sensory only stimulation, and show an important role for active self-touch in the formation of bodily self

Spatio-Temporal Brain Dynamics of the Feeling of a Presence

The Feeling of a Presence (FoP) is the strange sensation of perceiving someone close by, when no one is actually there. Although it is not perceived in any of the usual senses it is described as a strong feeling. The random nature and short duration of this psychotic hallucination, that mostly affects neurological patients, has made it quite difficult to study it in controlled conditions. In 2014, a paper published by Olaf Blanke described the first experiment inducing the FoP in healthy individuals, achieved through sensorimotor mismatches generated by an illusory self-touch paradigm. Setting out to continue this investigation, we used the same robotic setup from 2014 that allows participants to stimulate themselves on the back, adding several protocols of synchronicity to study the temporal dynamics of the FoP. To address the neural correlates of the FoP, we used Electroencephalography (EEG) and a new strategy of data analysis, in the field of EEG, by applying a General Linear Model to our data. Our results show that the subjective experience of the Feeling of a Presence, grows in a sigmoidal fashion with increasing delays, doubling its appearance from 100 msec to 400 msec of delay. The applied model, revealed significant effects of, the experimental conditions of synchronicity and from the interaction of these and the subjective experience of the FoP. When analyzing the brain sources, our data shows that both Secondary Somatosensory Cortex and Inferior Parietal Lobule are less activated when experiencing the FoP (compared when not experiencing the FoP), at respective latencies that match the components P100 and N140. The presented data helps advance the knowledge of this psychotic trait. Studying the development of the FoP on healthy individuals, might lead to a better understanding of what happens in patients with positive symptoms of psychosis

Exploring Teleimpedance and Tactile Feedback for Intuitive Control of the Pisa/IIT SoftHand

This paper proposes a teleimpedance controller with tactile feedback for more intuitive control of the Pisa/IIT SoftHand. With the aim to realize a robust, efficient and low-cost hand prosthesis design, the SoftHand is developed based on the motor control principle of synergies, through which the immense complexity of the hand is simplified into distinct motor patterns. Due to the built-in flexibility of the hand joints, as the SoftHand grasps, it follows a synergistic path while allowing grasping of objects of various shapes using only a single motor. The DC motor of the hand incorporates a novel teleimpedance control in which the user's postural and stiffness synergy references are tracked in real-time. In addition, for intuitive control of the hand, two tactile interfaces are developed. The first interface (mechanotactile) exploits a disturbance observer which estimates the interaction forces in contact with the grasped object. Estimated interaction forces are then converted and applied to the upper arm of the user via a custom made pressure cuff. The second interface employs vibrotactile feedback based on surface irregularities and acceleration signals and is used to provide the user with information about the surface properties of the object as well as detection of object slippage while grasping. Grasp robustness and intuitiveness of hand control were evaluated in two sets of experiments. Results suggest that incorporating the aforementioned haptic feedback strategies, together with user-driven compliance of the hand, facilitate execution of safe and stable grasps, while suggesting that a low-cost, robust hand employing hardware-based synergies might be a good alternative to traditional myoelectric prostheses

The Emergence of International Property Law

This Article explores a new field: international property law. International law increasingly creates, regulates, or otherwise affects the property rights of individuals, business entities, and other non-state actors. Globalization, democratic reforms, technology, and human rights principles have all contributed to this development. The Article begins by examining the unsuccessful effort to create a broad, internationally-enforceable human right to property during the second half of the twentieth century. Despite this failure, international property law doctrines have evolved in specialized contexts over recent decades. The Article demonstrates that these doctrines stem from four sources: (a) regulation of the global commons; (b) coordination of transboundary property rights; (c) adoption of global policies to prevent specific harms; and (d) protection of the human rights of vulnerable groups. Finally, the Article argues that the time has come to recognize international property law as a discrete subject, and thereby promote its coherent evolution in future decades. The Article discusses the value of recognizing international property law, explores an international definition of property

The Emergence of International Property Law

This Article explores a new field: international property law. International law increasingly creates, regulates, or otherwise affects the property rights of individuals, business entities, and other non-state actors. Globalization, democratic reforms, technology, and human rights principles have all contributed to this development. The Article begins by examining the unsuccessful effort to create a broad, internationally-enforceable human right to property during the second half of the twentieth century. Despite this failure, international property law doctrines have evolved in specialized contexts over recent decades. The Article demonstrates that these doctrines stem from four sources: (a) regulation of the global commons; (b) coordination of transboundary property rights; (c) adoption of global policies to prevent specific harms; and (d) protection of the human rights of vulnerable groups. Finally, the Article argues that the time has come to recognize international property law as a discrete subject, and thereby promote its coherent evolution in future decades. The Article discusses the value of recognizing international property law, explores an international definition of property