When pliers become fingers in the monkey motor system

doi:10.1073/pnas.0705985105

When pliers become fingers in the monkey motor system

Dipartimento di Neuroscienze, Università di Parma, Via Volturno 39, 43100 Parma, Italy

Edited by Emilio Bizzi, Massachusetts Institute of Technology, Cambridge, MA, and approved December 4, 2007 (received for review June 27, 2007)

Abstract

The capacity to use tools is a fundamental evolutionary achievement. Its essence stands in the capacity to transfer a proximal goal (grasp a tool) to a distal goal (e.g., grasp food). Where and how does this goal transfer occur? Here, we show that, in monkeys trained to use tools, cortical motor neurons, active during hand grasping, also become active during grasping with pliers, as if the pliers were now the hand fingers. This motor embodiment occurs both for normal pliers and for “reverse pliers,” an implement that requires finger opening, instead of their closing, to grasp an object. We conclude that the capacity to use tools is based on an inherently goal-centered functional organization of primate cortical motor areas.

Footnotes

^‡To whom correspondence should be addressed: E-mail: giacomo.rizzolatti{at}unipr.it
Author contributions: M.A.U., F.G., V.G., and G.R. designed research; M.A.U., L.E., I.I., M.R., F.C., A.J., and V.G. performed research; M.A.U., L.E., M.R., F.C., and A.J. analyzed data; and M.A.U. and G.R. wrote the paper.
↵*Present address: Department of Neurobiology and Behavior, University of California, 2205 McGaugh Hall, Irvine, CA 92697-4550.
↵ ^†Present address: Laboratoire de Neurobiologie et Psychopathologie, Université de Nice, Parc Valrose 06108, Nice Cedex 2, France.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
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