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# Neuromarkers of real touch vs. illusory touch

Emile Savalle, Léa Pillette, Kyungho Won, Ferran Argelaguet, Anatole Lécuyer, Marc J.-M. Macé

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## ► To cite this version:

Emile Savalle, Léa Pillette, Kyungho Won, Ferran Argelaguet, Anatole Lécuyer, et al., Neuromarkers of real touch vs. illusory touch. CORTICO 2024 - Journées du COLlectif pour la Recherche Transdisciplinary sur les Interfaces Cerveau-Ordinateur, May 2024, Nancy, France. pp.1-2. [hal-04607878](https://hal.science/hal-04607878)

HAL Id: hal-04607878

https://hal.science/hal-04607878

Submitted on 11 Jun 2024

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

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Distributed under a Creative Commons Attribution 4.0 International License
# Neuromarkers of real touch vs. illusory touch

Emile Savalle, Léa Pillette, Kyungho Won, Ferran Argelaguet, Anatole Lécuyer, Marc J.-M. Macé

<figure><img src="image_1.png" /></figure>

## To cite this version:

Emile Savalle, Léa Pillette, Kyungho Won, Ferran Argelaguet, Anatole Lécuyer, et al., Neuromarkers of real touch vs. illusory touch. CORTICO 2024 - Journées du COLlectif pour la Recherche Transdisciplinaire sur les Interfaces Cerveau-Ordinateur, May 2024, Nancy, France. pp.1-2. hal-04607878

HAL Id: hal-04607878

https://hal.science/hal-04607878v1

Submitted on 11 Jun 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>
CORTICO 2024

Neuromarkers of real touch vs. illusory touch

Emile Savalle<fnref n="1" />, Léa Pillette<fnref n="2" />, Kyungho Won<fnref n="1" />, Ferran Argelaguet<fnref n="1" />, Anatole Lécuyer<fnref n="1" />,
and Marc J-M Macé<fnref n="2" />

Haptic feedback allows virtual reality (VR) users to physically interact with virtual content. How-
ever, due to the limitations on haptic technology, delivering haptic feedback is still challenging [1]. To
overcome such limitations, alternative methods leverage visual dominance to induce haptic illusions [2].

A few studies investigated the effects of tactile stimuli on user perception through EEG in VR, such as for texture discrimination [3] or to study social touch [4]. However, there is room for understanding the brain activity during the perception of tactile stimuli within Virtual Environment (VE) [3].

This abstract describes an experimental protocol, which aims to investigate the brain activity in response to the anticipation and perception of physical and virtual touch, and the impact of the virtual body representation.

During the experiment, users will be immersed in a virtual environment replicating the real en-
vironment, including a desk, their body, and a robotic arm. Touch stimulation will be generated
haptically, a gentle physical touch on the back of the hand using a robotic arm (see Fig. 1), and/or
visually, a visual stimulation matching the motion of the robot in VR. The experiment will have two
within-subjects factors. Touch stimulation, either coherent visual and tactile touch feedback or just
visual touch; and body representation, realistic human avatar or geometric body representation, as we
hypothesize that body representation and ownership will alter the user's perception.

We will study the impact of our design on two aspects:

* Anticipation of touch: Brain activity preceding touch using contingent negative variation

* Perception of touch: Somatosensory cortex response with somatosensory evoked potential and mirror neuron system activation

Our results could provide insights about perception and anticipation of illusory and real touch by
observing relevant neuromarkers.

<footnote n="1">¹Inria, Univ. Rennes, IRISA, CNRS – F35000 Rennes, France.</footnote>

<footnote n="2">²Univ. Rennes, Inria, CNRS, IRISA – F35000 Rennes, France.</footnote>
Neuromarkers of real touch vs. illusory touch

Emile Savalle¹, Léa Pillette², Kyungho Won¹, Ferran Argelaguet¹, Anatole Lécuyer¹, and Marc J-M Macé²

¹Inria, Univ. Rennes, IRISA, CNRS – F35000 Rennes, France.

²Univ. Rennes, Inria, CNRS, IRISA – F35000 Rennes, France.

Haptic feedback allows virtual reality (VR) users to physically interact with virtual content. However, due to the limitations on haptic technology, delivering haptic feedback is still challenging [1]. To overcome such limitations, alternative methods leverage visual dominance to induce haptic illusions [2].

A few studies investigated the effects of tactile stimuli on user perception through EEG in VR, such as for texture discrimination [3] or to study social touch [4]. However, there is room for understanding the brain activity during the perception of tactile stimuli within Virtual Environment (VE) [3].

This abstract describes an experimental protocol, which aims to investigate the brain activity in response to the anticipation and perception of physical and virtual touch, and the impact of the virtual body representation.

During the experiment, users will be immersed in a virtual environment replicating the real environment, including a desk, their body, and a robotic arm. Touch stimulation will be generated haptically, a gentle physical touch on the back of the hand using a robotic arm (see Fig. 1), and/or visually, a visual stimulation matching the motion of the robot in VR. The experiment will have two within-subjects factors. Touch stimulation, either coherent visual and tactile touch feedback or just visual touch; and body representation, realistic human avatar or geometric body representation, as we hypothesize that body representation and ownership will alter the user's perception.

We will study the impact of our design on two aspects:

* Anticipation of touch: Brain activity preceding touch using contingent negative variation

* Perception of touch: Somatosensory cortex response with somatosensory evoked potential and mirror neuron system activation

Our results could provide insights about perception and anticipation of illusory and real touch by observing relevant neuromarkers.
References

[1] Wang Dangxiao, GUO Yuan, LIU Shiyi, Yuru Zhang, Xu Weiliang, and Xiao Jing. Haptic display for virtual reality: progress and challenges. *Virtual Reality & Intelligent Hardware*, 1(2):136–162, 2019.

[2] Susan J Lederman and Lynette A Jones. Tactile and haptic illusions. *IEEE Transactions on Haptics*, 4(4):273–294, 2011.

[3] Anne Margarette S Maallo, Basil Duvernoy, Håkan Olausson, and Sarah McIntyre. Naturalistic stimuli in touch research. *Current Opinion in Neurobiology*, 75:102570, 2022.

[4] Niklas Ravaja, Ville Harjunen, Imtiaj Ahmed, Giulio Jacucci, and Michiel M Spapé. Feeling touched: Emotional modulation of somatosensory potentials to interpersonal touch. *Scientific reports*, 7(1):40504, 2017.

<figure><img src="image_4.png" /><figcaption>Figure 1: Experimental setup. 1: 6-axis collaborative Universal Robot UR5. 2: Leap Motion for hand tracking. 3: HMD VR headset. 4: EEG headset.</figcaption></figure>
References

[1] Wang Dangxiao, GUO Yuan, LIU Shiyi, Yuru Zhang, Xu Weiliang, and Xiao Jing. Haptic display for virtual reality: progress and challenges. *Virtual Reality & Intelligent Hardware*, 1(2):136–162, 2019.

[2] Susan J Lederman and Lynette A Jones. Tactile and haptic illusions. *IEEE Transactions on Haptics*, 4(4):273–294, 2011.

[3] Anne Margarette S Maallo, Basil Duvernoy, Håkan Olausson, and Sarah McIntyre. Naturalistic stimuli in touch research. *Current Opinion in Neurobiology*, 75:102570, 2022.

[4] Niklas Ravaja, Ville Harjunen, Imtiaj Ahmed, Giulio Jacucci, and Michiel M Spapé. Feeling touched: Emotional modulation of somatosensory potentials to interpersonal touch. *Scientific reports*, 7(1):40504, 2017.

<figure><img src="image_3.png" /><figcaption>Figure 1: Experimental setup. 1: 6-axis collaborative Universal Robot UR5. 2: Leap Motion for hand tracking. 3: HMD VR headset. 4: EEG headset.</figcaption></figure>