Body Representation: Insights from Health to Pathological Models

Body representation is a dynamic concept and refers both to stable and adaptable components of how the brain integrates multisensory information relative to body (such as position, posture, shape etc.) and related cognitive and affective processes (body knowledge, beliefs, feelings etc.). Here we explore various aspects of body representation in healthy and pathological models, including its neural basis, plasticity, and its role in conditions like phantom limb pain (PLP). Firstly, we affirm the presence of a standard postural representation of the hand, underlining its neural origin. This unveils the existence of a predetermined and stable component within body representation. Understanding the neural circuits governing this standard posture could open new avenues for therapeutic interventions, particularly in prosthetic and rehabilitative contexts. Furthermore, we explore the malleability of body representation using virtual reality, demonstrating how visual feedback can impact the perceived dimensions of one's body. This visual influence offers perspectives into the potential of virtual reality in modifying body image and discloses how exteroception and proprioception differ in how they may respond to manipulation of vision. Shifting our focus to clinical contexts, we investigate PLP as a consequence of altered body representations after amputation. By discussing various physiological models, we uncover the multifaceted nature of the disorder. Our analysis suggests that effective treatments for PLP may require a comprehensive approach, tailored to individual needs. Building on this analysis, we delved deeper into one of the emerged causes of PLP investigating in a virtual reality environment how incongruence between pre-represented and actual body appearance can exacerbate pain perception and modulate autonomic responses. We disclosed an intricate relationship between visual feedback alteration, body image-related unpleasantness, and virtual reality immersion quality. Finally, we emphasise the importance of incorporating non-invasive proprioceptive feedback strategies in the recovery of altered body representation. While no one-size-fits-all approach is identified, we delineate the advantages and disadvantages of various methods, offering guidance for future interventions. This project aims to disentangle the complex interplay between stable and plastic elements of body representation, offering insights into potential therapeutic strategies for conditions such as PLP in attempt to pave the way for further research in this field.