No effect of the short-term learning of object trajectories on multisensory perception within the peripersonal space.

Peripersonal space, the space immediately surrounding the body, functions as an interface between the self and the external environment. In interactions with dynamic environments, not only bodily information but also accurate estimation of the dynamics of external objects is required. While numerous studies have demonstrated that real-time estimation of object dynamics, based on bottom-up mechanisms, modulates peripersonal space representation, little evidence supports the involvement of top-down knowledge about object dynamics in shaping peripersonal space. In the present study, we conducted two experiments to examine whether pre-learned statistical regularities of object trajectories influence performance in a visuo-tactile task designed to assess multisensory perception within the peripersonal space. Participants first learned the statistical tendencies of visually presented object movements, and subsequently performed a visuo-tactile reaction task. Across both experiments, we observed no significant changes in task performance as a function of the learned object dynamics. These findings call for a reconsideration of the role of top-down knowledge in the modulation of peripersonal space representation.