Dealing with the world close to our body. Characterizing determinants of peripersonal space plasticity

The human brain has evolved a highly plastic system to map the space immediately surrounding the body: the peripersonal space (PPS). This system dynamically expands in response to sensorimotor stimulation, adapting to new action possibilities and environmental contexts. However, little is still known about the mechanisms driving PPS plasticity. In this study, we systematically investigated the sensory, motor, spatial and bodily posture determinants of PPS plasticity (PPSp) in a comprehensive design of 4 experiments with 289 participants. Our findings reveal distinct and complementary roles for each determinant, showing that PPSp is influenced by motor and spatial determinants, while sensory and bodily posture determinants do not exert a significant influence on its plastic properties. These results thus establish PPSp as a multimodal, effector-dependent, multi-frame and posture-invariant system. These findings determine PPSp as a dynamic and adaptive system, finely tuned through evolution to support ever-changing interactions with both physical and social environments.