Prehension is really reaching and grasping

Journal article (2007)

Authors

C. van de Kamp University Medical Center Groningen
Frank T.J.M. Zaal University Medical Center Groningen
Affiliation
External organisation
More Info
expand_more

Published Date

2007

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Affiliation

External organisation

Abstract

Prehension has traditionally been seen as the act of coordinated reaching and grasping. However, recently, Smeets and Brenner (in Motor Control 3:237-271, 1999) proposed that we might just as well look at prehension as the combination of two independently moving digits. The hand aperture that has featured prominently in many studies on prehension, according to Smeets and Brenner's "double-pointing hypothesis", is really an emergent property related to the time course of the positions of the two digits moving to their respective end points. We tested this double-pointing hypothesis by perturbing the end position of one of the digits while leaving the end position of the opposing digit unchanged. To this end, we had participants reach for and grasp a metallic object of which the side surfaces could be made to slide in and out. We administered the perturbation right after movement initiation. On several occasions, after perturbing the end position of one digit, we found effects also on the kinematics of the opposing digit. These findings are in conflict with Smeets and Brenner's double-pointing hypothesis.