euro7curieBODILYSELF: Vestibular and multisensory investigations of bodily self-consciousness

Project 333607 funded under FP7-PEOPLE Marie Curie Career Integration Grant from 01/10/2013 to 30/09/2017

Principal Investigator: Dr. Christophe Lopez, CNRS

Host Institution: Centre National de la Recherche Scientifique (CNRS)

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SUMMARY AND OBJECTIVES OF THE PROJECT

Multisensory processing has been proven to be of key importance for bodily experiences and the self, although research has focused mostly on the contribution of visual and somatosensory signals. The investigation of vestibular signals has received much less attention despite its key importance in coding whole-body motion and orientation in space. The BODILYSELF Project plans to investigate vestibular contributions to whole-body experiences, in particular self-location, first-person perspective taking and self-other distinction and mirroring. For this, vestibular physiology will be linked with neuroimaging and cognitive science of the self. We will use artificial stimulation of the vestibular system and multisensory conflicts – in combination with electroencephalography and fMRI – to explore the mechanisms of bodily self-consciousness. The strength and novelty of the BODILYSELF Project lies in joining approaches from cognitive neuroscience, vestibular physiology and oto-neurology, in collaboration with a philosopher of mind, for a common goal. This may lead to findings that are relevant across research fields in the cognitive neurosciences of the self, philosophy of mind, neurology and oto-neurology.

MAIN QUESTIONS AND ACHIEVEMENTS

1) Is vestibular information used for changing the viewpoint?

We combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar’s viewpoint. In a control experiment, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Vestibular stimulation did not affect mental rotation.

In conclusion, vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centred mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others’ actions.

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See the original publication: Deroualle D., Borel L., Devèze A., and Lopez C. “Changing Perspective: The Role of Vestibular Signals.” Neuropsychologia, 2015. doi:10.1016/j.neuropsychologia.2015.08.022. 

2) Do vestibular disorders modify perspective taking?

In collaboration with the Otorhinolaryngology Department of La Conception Hospital (Prof. J.P. Lavieille) in Marseille, we evaluate the consequence of unilateral vestibular deafferentation (acoustic neurinoma) for the patient’s ability to change perspective.

Published abstract: Deroualle D., Borel L., Devèze A., and Lopez C. “Les Informations Vestibulaires Influencent La Prise de Perspective D’autrui : Études Chez Des Volontaires Sains et Implications Pour La Réhabilitation Vestibulaire.” Neurophysiologie Clinique/Clinical Neurophysiology 44(5), 2014: 493. doi:10.1016/j.neucli.2014.09.008.

3) Do vestibular signals contribute to social cognition?

We have reviewed several lines of evidence indicating that vestibular signals may be involved in the sensory bases of self-other distinction and mirroring, emotion perception and perspective taking.

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See the open access article: Deroualle, D. and Lopez C. “Toward a Vestibular Contribution to Social Cognition.” Frontiers in Integrative Neuroscience 8 (2014): 16. doi:10.3389/fnint.2014.00016. 

Another article, in collaboration with Dr Caroline Falconer (University of Nottingham) and Prof Fred Mast (University of Bern) deals more specifically with how the social context influences more global self-perceptions. In this article, we outline previously overlooked areas of research to bridge the distinct field of social neuroscience with global self-perception, vestibular processing and postural control.

See the original article: Lopez, Falconer, Deroualle and Mast (2015) In the presence of others: self-location, balance control and vestibular processing. Neurophysiologie Clinique/Clinical Neurophysiology. In press. NEUCLI-D-15-00022R1.

4) Do vestibular disorders impair bodily self-consciousness?

The consequences of vestibular disorders on balance, oculomotor control and self-motion perception have been extensively described in humans and animals. More recently, vestibular disorders have been related to cognitive deficits in spatial navigation and memory tasks. Less frequently, abnormal bodily perceptions have been described in patients with vestibular disorders. Altered forms of bodily self-consciousness include distorted body image and body schema, disembodied self-location (out-of-body experience), altered sense of agency, as well as more complex experiences of dissociation and detachment from the self (depersonalization). In this article, I suggest that vestibular disorders create sensory conflict or mismatch in multisensory brain regions, producing perceptual incoherence and abnormal body and self perceptions. This hypothesis is based on recent functional mapping of the human vestibular cortex, showing vestibular projections to the primary and secondary somatosensory cortex and in several multisensory areas found to be crucial for bodily self-consciousness.

See the open access article: Lopez, C. “A Neuroscientific Account of How Vestibular Disorders Impair Bodily Self-Consciousness.” Frontiers in Integrative Neuroscience 7 (2013): 91.

5) What are the vestibular contributions to human self-consciousness?

Together with Dr. Bigna Lenggenhager (University of Zürich), we have contributed to an open access collection of articles edited by the German philosophers Prof. Thomas Metzinger and Dr. Jenny Windt: OPEN MIND, collecting cutting-edge articles about philosophy of mind and the cognitive neuroscience of mind, self and consciousness (see: http://open-mind.net).

See the open access article: Lenggenhager B. and Lopez C. “Vestibular Contributions to the Sense of Body, Self, and Others.” In Open MIND, edited by T. Metzinger and J. M. Windt, 1–38. Frankfurt am Main: MIND-Group, 2015.

We have confronted our opinions about vestibular perception and the vestibular contributions to self-consciousness with a philosopher of mind, Dr. Adrian Alsmith (University of Copenhagen), who is a collaborator of the BODILYSELF project.

See the open access articles: Alsmith, A. “Perspectival Structure and Vestibular Processing. A Commentary on Bigna Lenggenhager and Christophe Lopez.” In Open MIND, edited by T. Metzinger and J. M. Windt. Frankfurt am Main: MIND-Group, 2015. 

Lenggenhager B. and Lopez C. “Vestibular Sense and Perspectival Experience. A Reply to Adrian Alsmith.” In Open MIND, edited by T. Metzinger and J. M. Windt, 1–9. Frankfurt am Main: MIND-Group, 2015.

6) Vestibular stimulation as a therapeutic tool for neurological and psychiatric patients?

Capture d’écran 2015-10-13 à 17.49.19The probable relevance of galvanic and caloric vestibular stimulations for rehabilitation of neurological and psychiatric disorders is the topic of a research article in press in Current  Opinion in Neurology. Lopez et al. (forthcoming).

7) Electrophysiological investigations of vestibular processing: electromyography and electroencephalography

We are currently investigating how the central nervous system processes vestibular signals using non-invasive surface electromyography and scalp electroencephalography (64-channel BIOSEMI system) in healthy volunteers. State-of-the-art
 electrophysiological approaches, combined with experimental paradigms from social and cognitive neurosciences, should reveal the vestibular contributions to perspective taking.

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OUTREACH ACTIVITIES AND INCREASE IN PUBLIC AWARENESS ABOUT VESTIBULAR PROCESSING AND SELF-CONSCIOUSNESS

1) Special issue in “Frontiers in Integrative Neuroscience”

Capture d’écran 2015-10-14 à 18.30.02Christophe Lopez (CNRS, Aix-Marseille University, France) has co-edited the Special issue “The vestibular system in cognitive and memory processes in mammals” together with Prof. Pierre Denise (Univ. Caen, France), Prof. Thomas Brandt (Univ. Munich, Germany), Prof. Paul Smith (Univ. Otago, New Zealand) and Dr. Stéphane Besnard (INSERM, Univ. Caen, France). The special issue is a collection of 24 articles written by the leading experts in the field of vestibular cognition and vestibular neuroscience.

2) “Fête de la Science” at Aix-Marseille University

Capture d’écran 2015-10-14 à 18.39.15Christophe Lopez, Diane Deroualle and Liliane Borel host high school students in the Laboratory of Integrative and Adaptive Neuroscience at Aix Marseille University for one day. Students are involved in experimental designs used in the research area of the BODILYSELF project, including testing the “rubber hand illusion” and the “full body illusion”.

3) Communication to non expert public in the field
Christophe Lopez presented the contribution of the vestibular organs to balance control and space perception in a public conference at La Cité des Sciences et de l’Industrie (Paris, France). The conference was followed by an hour of questions with a non expert audience, increasing public awareness about balance disorders and rehabilitation. The conference is available online here.

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4) An article about consciousness in a public science journal
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An article by Christophe Lopez and Olaf Blanke was published (October 2015) in a famous French public science journal (La Recherche) for a special issue on “Consciousness”.