The parietal lobe and tool use

The ability to craft and use tools is a crucial skill of human beings, distinguishing humans from all other species. Humans show a unique capacity to create novel, technologically advanced devices and represent physical causality using tools. In the present chapter we review the effect of tool use in changing body-space multisensory integration and body representation and the fundamental contribution of the parietal lobe to the neural underpinnings of tool use. In the final section we briefly introduce the effect of parietal brain damage on tool use. At the beginning of 20th century, a crucial role for the left parietal lobe for a proper control of gestures, including the pantomimed and actual use of tools, was already clear. Actual available evidence supports a critical role of the parietal lobe for both the lower-level multisensory integration of somatosensory and visual input necessary for the interactions between body, tools, and external objects, and for the representation of the mechanical and conceptual dynamics of tool use. Parietal regions, rather than merely representing the prototypical use of a tool, would be critical to understand the general mechanical interactions of the tool with the environment. The increase of knowledge about such brain mechanisms is of utmost relevance in the present times, characterized by the development of more and more sophisticated technological tools, such as functional prostheses, robotic interfaces, and virtual-reality devices.