Body ownership alterations in stroke emerge from reduced proprioceptive precision and damage to the frontoparietal network

Stroke patients often experience alterations in their subjective feeling of ownership for the affected limb, which can hinder motor function and interfere with rehabilitation. In this study, we aimed at disentangling the complex relationship between sensory impairment, body ownership (BO), and motor control in stroke patients. We recruited 20 stroke patients with unilateral upper limb sensory deficits and 35 age-matched controls. Participants performed a virtual reality reaching task with a varying displacement between their real unseen hand and a visible virtual hand. We measured reaching errors and subjective ownership ratings as indicators of hand ownership. Reaching errors were modeled using a probabilistic causal inference model, in which ownership for the virtual hand is inferred from the level of congruency between visual and proprioceptive inputs and used to weigh the amount of visual adjustment to reaching movements. Stroke patients were more likely to experience ownership over an incongruent virtual hand and integrate it into their motor plans. The model explained this tendency in terms of a decreased capability of detecting visuo-proprioceptive incongruences, proportionally to the amount of proprioceptive deficit. Lesion analysis further revealed that BO alterations, not fully explained by the proprioceptive deficit, are linked to frontoparietal network damage, suggesting a disruption in higher-level multisensory integration functions. Collectively, our results show that BO alterations in stroke patients can be quantitatively predicted and explained in a computational framework as the result of sensory loss and higher-level multisensory integration deficits. Swiss National Science Foundation (163951). • Brain stroke alters limb ownership and motor planning based on visual feedback • Unisensory and multisensory components of these alterations can be disentangled • Probabilistic inference accounts for these alterations in terms of proprioceptive loss • Higher-level multisensory integration deficits are linked to frontoparietal damage Stroke patients can experience alterations in their subjective feeling of ownership for the affected limb, which can hinder motor function and interfere with rehabilitation. Mastria et al. show that patients are more likely to integrate incongruent visual feedback about their affected limb (i.e., a displaced virtual hand) into their motor plans and feel ownership for it. Modeling body ownership as the result of causal inference on multisensory stimuli, these alterations can be explained as emerging from proprioceptive deficits. Damage to the frontoparietal network can further disrupt the causal inference process , leading to higher-level multisensory integration and body ownership deficits. Disentangling components of body ownership alterations can help to better understand these deficits and tailor rehabilitation strategies. Stroke patients experience alterations in their subjective feeling of ownership for the affected limb, which can hinder motor function and interfere with rehabilitation. Using computational modeling and lesion analysis, Mastria et al. show that these alterations result from the combination of proprioceptive and high-level multisensory integration deficits due to frontoparietal damage.