Plasticity and tool use in the body schema

The ability of humans to manufacture objects and represent physical causality makes them the master species in the use of tools. What is the impact of such a specific skill on the processing of bodily body-related spatial information? To what extent does the skilful manipulation of tools require specific embodiment of the device into one’s body representation? The present chapter reviews the effect of tool use on the representation of the body and space surrounding it, by analysing the cognitive effects of tool use and its neural representations. Studies on animals, healthy humans, and neuropsychological patients suggest that multisensory integration of stimuli far from the body is enhanced when a tool can reach those stimuli. Such a spatial remapping indicates that the body schema may adapt to include the device into one’s body representation. Notably, tool use-related changes are not limited to spatial processing, but also to the processing of body-related sensory-motor information. Understanding the cognitive mechanisms underlying tool use and the effect of tool use in the representation of the space around us is a paramount challenge to the understanding of body representation, especially considering that modern and more sophisticated technological tools, such as functional prostheses, robotic interfaces, and virtual reality devices, continually shape the central role of the body in human–environment interactions.