Visuo-Tactile Integration and Body Ownership in the Human Brain

Study Overview
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Brief Summary
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The present project exploits brain imaging and neuroscience robotics to investigate the role of quantifiable visual input on the relationship between visuo-tactile integration and body ownership (the feeling that this body belongs to me).

Detailed Description
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Observational study, fundamental research, multicentric, national. The analysis of questionnaires, self-reports, and brain imaging associated with the RHI is used to understand the influence of visual input on body ownership. To this aim, participants lay down in the magnetic resonance (MR) scanner (Figure 1B), are presented with visual stimuli (videos of the virtual rubber hand - visual stroking) simultaneously in real time with tactile stimuli (robotic stroking of the participant's hand - tactile stroking), and in combination or not with the measurement of autonomic arousal (GSR) associated with the observation of a video showing the virtual rubber hand in a threatening situation (e.g. a knife approaching the virtual hand - unconscious RHI effects). By means of structured questionnaires and semi-structured self-reports, participants (i) evaluate eventual sensations felt during the visuo-tactile stimulation and (ii) report the personal feelings and impressions about body ownership for the virtual rubber hand (conscious RHI effects).

Official Title
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Visuo-Tactile Integration and Body Ownership in the Human Brain

Conditions
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Behavior and Behavior Mechanisms, Body Representation

Intervention / Treatment
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* Behavioral: Visuo-tactile stimulations of the right hand


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: general health personal interest age between 18 and 55 years old fulfil standard guidelines for fMRI studies Exclusion Criteria: history of seizures, epilepsy specific medications or treatment concomitant diseases (e.g. cardiopathy) pregnancy unexplained loss of consciousness chronic headaches neurological illnesses head concussion, presence of metal in the neck or head implanted medical devices drug abuse inability to give consent

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MR imaging<br>The experiment is aimed to induce a virtual rubber hand illusion, in which the individuals can potentially experience an embodiment illusion | Behavioral: Visuo-tactile stimulations of the right hand<br>* Participants lay down in the magnetic resonance (MR) scanner are presented with visual stimuli (videos of the virtual rubber hand - visual stroking) simultaneously in real time with tactile stimuli (robotic stroking of the participant's hand - tactile stroking). An MR-compatible robot systematically provides the tactile stroking on the participant's hand. MR-compatible goggles show the visual stroking. Patterns of long and short robotic movements will be provided.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neuro-behavioral changes associated with vision-dependent alterations of body ownership, measured via brain activity (fMRI) | Analysis of objective measures of the RHI | Through study completion, an average of 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective Experience via VAS scale | To understand the variations of the body ownership, Visual Analogic Scale, values 0 to 7, 0 = no illusory body ownership, 7 = strong illusory body ownership | Through study completion, an average of 2 years | 
| Automatic response (skin conductance) | Measure of the skin conductance response (SCR, measured in siemens) during experiment runs, which is an indirect measure of sympathetic activity. Compare the blocks in which a pre-recorded visual threat (a video in which a hand is being pricked by a syringe needle) with baseline blocks and expect a higher SCR signal during visual threat blocks compared to the baseline. The SCR will be measured through a device connected to a dedicated laptop and electrodes that will be attached to the left index and middle fingers from participants. The SCR will be saved in log files and estimated a posteriori for each block using a general linear model and the weight regressors will be compared. There are no risks to the participants (since it is a passive measurement) the electrodes are compatible to the magnetic resonance environment. | Through study completion, an average of 2 years |