Interoceptive conditioning to counteract distortions in bodily self-representations in anorectic patients

Bodily self-consciousness arises from the integration of exteroceptive and interoceptive signals, which together shape the brain’s probabilistic representation of the body as “self.” Within the predictive coding framework, this process is guided by the relative precision of sensory inputs, with the brain favoring the most reliable signals in a given context. Research has shown that Interpersonal Multisensory Stimulation (IMS)— particularly visuo-tactile stimulation from a first-person perspective—can induce the illusion of ownership over a virtual body (embodiment) and modulate bodily self-representations. In patients with Anorexia Nervosa (AN)—who display reduced interoceptive abilities and heightened susceptibility to body illusions—exteroceptive IMS altered perceived body size. Embodiment of an idealized, underweight avatar led to a transient sensation of being thinner, while embodiment of a self-similar, normal-weight avatar increased body size overestimation. These findings suggest that IMS-driven plasticity may only occur in directions consistent with preexisting distortions, reinforcing maladaptive body image. To address this limitation, we propose integrating interoceptive signals into IMS paradigms to enhance embodiment and recalibrate distorted body representations in AN patients. In Study 1, in an immersive virtual reality setup, we provided avatars (underweight or normal weight) with synchronous/asynchronous breathing signals and visuo-tactile IMS, and measured changes in embodiment strength and body image distortions. Preliminary results on healthy participants showed stronger embodiment for the normal-weight avatar in the synchronous condition. Conversely, asynchronous IMS with the normal-weight avatar increased body dissatisfaction and reduced the feeling of being thinner than usual. In Study 2, we will use an interoceptive-exteroceptive conditioning paradigm, pairing an underweight avatar (matched to actual body size) with synchronous breathing, and a normal-weight avatar (matched to distorted perception) with antiphase breathing. This aims to decouple multisensory congruence from distorted self-representations. These findings may inform novel multisensory-based interventions for AN and underscore the role of interoception in bodily self-consciousness.