Peripersonal Space and Body Schema: Two Labels for the Same Concept?

To sensibly interact with the environment, like when grasping objects and navigating through space, the brain needs to compute not only target- and environment-related inputs, but also the size and spatial location of the entire body as well as of its parts. The neuronal construction and dynamic updating throughout the entire life of this bodily representation, commonly termed body schema in the literature, appears essential for efficient motor control and skilful tool-use. Meanwhile, recent contributions to the study of spatial multisensory processing have identified the peripersonal space as a particular region surrounding the body that acts as an interface between the body and the environment, for defensive and/or purposeful actions toward objects. In addition, the peripersonal space features plastic properties following tool-use that largely overlap those originally ascribed to the body schema, and have been actually interpreted as reflecting changes in the body schema itself. Here we seek to provide operational definitions and neuronal bases for each of these concepts, questioning whether sufficient evidence exists for them to be considered as the two faces of the same coin.