Institut Jean Nicod

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Soutenance de thèse - Victor Pitron - "How bodily awareness takes shape : insights from disorders on body representations"

 

Date  : Vendredi 7 mai 2021 à 14h00

Lieu : Par visioconférence, en anglais. 

 

Jury :

  • Pr Cédric Lemogne (Président, Paris)
  • Pr Olaf Blanke (Rapporteur, Genève)
  • Pr Marcello Costantini (Rapporteur, Chieti-Pescara)
  • Pr Peter Henningsen (Examinateur, München)
  • Dr Catherine Tallon-Baudry (Examinatrice, Paris)
  • Dr Frédérique de Vignemont (Directrice de thèse, Paris)

 

Résumé :

Investigations about the awareness of one’s own body have bloomed in the last decades. In particular, the concept of body representations has gained much emphasis. It is generally assumed that two main body representations separate : the body image and the body schema. The former body representation underlies the perception of one’s own body ; the latter underlies action control. In this thesis, I theoretically and empirically investigate body representations in light of distorted bodily experiences of patients with neurological and psychiatric disorders. I focus on three main questions. Firstly, beyond the differences between the body schema and the body image, what are their ways of interactions ? The proposal is that the two representations are not independent. On the contrary, they are in constant interplay partly reshaping each other. It is therefore postulated a co-constructed model of the body image and the body schema. Furthermore, the body schema might have some primacy over the body image, the former preceding and grounding the shaping of the latter. In a second part of this work, I turn to the awareness of the internal body. How are experiences about one’s own organs represented ? The question has been largely overlooked in the literature on body representations. Here, it is proposed that a specific inner body map structures the awareness of the internal body. More, the construction of the inner body map mostly relies on prior information about of the body, thereby distinguishing from the body schema and the body image whose construct relies more on sensory cues. Distortions of the inner body map can explain disorders of the awareness of the internal body, in particular persistent physical symptoms that do not rely on a lesion or malfunction of the body. The last question of this thesis is concerned by how body representations adapt in time. Sometimes, it seems that the role of body representations is to stand for missing sensory inputs from the body, thereby ensuring the coherence and the stability of bodily awareness over time. Conversely, in other cases it seems that the content of body representations changes quickly as in bodily hallucinations in which patients feel suddenly their own body with a different size and shape. How is the adaptiveness of body representations encoded ? One putative underlying mechanism might relate to signals from one’s own heartbeats. Here we go one step further. Across two behavioral experiments, it is shown that the decision whether to act or not is better performed in synchrony with heartbeats, further advocating for close relations between the internal and the external body. Overall, the work compiled in this thesis opens new avenues for further investigating body representations in light of patients’ distorted bodily experiences.


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