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Visuo-Tactile Integration and Body Ownership in the Human Brain

Not Applicable
Completed
Conditions
Body Representation
Behavior and Behavior Mechanisms
Interventions
Behavioral: Visuo-tactile stimulations of the right hand
Registration Number
NCT05164991
Lead Sponsor
Swiss Federal Institute of Technology
Brief Summary

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

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).

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
45
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

Study & Design

Study Type
INTERVENTIONAL
Study Design
SINGLE_GROUP
Arm && Interventions
GroupInterventionDescription
MR imagingVisuo-tactile stimulations of the right handThe experiment is aimed to induce a virtual rubber hand illusion, in which the individuals can potentially experience an embodiment illusion
Primary Outcome Measures
NameTimeMethod
Neuro-behavioral changes associated with vision-dependent alterations of body ownership, measured via brain activity (fMRI)Through study completion, an average of 2 years

Analysis of objective measures of the RHI

Secondary Outcome Measures
NameTimeMethod
Subjective Experience via VAS scaleThrough study completion, an average of 2 years

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

Automatic response (skin conductance)Through study completion, an average of 2 years

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.

Trial Locations

Locations (1)

ETH Zurich, Rehabilitation Engeineering Laboratory

🇨🇭

Zurich, Switzerland

ETH Zurich, Rehabilitation Engeineering Laboratory
🇨🇭Zurich, Switzerland
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