Abstract

Converging evidence shows that hand-actions are controlled at the level of synergies and not single muscles. One intriguing aspect of synergy-based action-representation is that it may be intrinsically sparse and the same synergies can be shared across several distinct types of hand-actions. Here, adopting a normative angle, we consider three hypotheses for hand-action optimal-control: sparse-combination hypothesis (SC) – sparsity in the mapping between synergies and actions - i.e., actions implemented using a sparse combination of synergies; sparse-elements hypothesis (SE) – sparsity in synergy representation – i.e., the mapping between degrees-of-freedom (DoF) and synergies is sparse; double-sparsity hypothesis (DS) – a novel view combining both SC and SE – i.e., both the mapping between DoF and synergies and between synergies and actions are sparse, each action implementing a sparse combination of synergies (as in SC), each using a limited set of DoFs (as in SE). We evaluate these hypotheses using hand kinematic data from six human subjects performing nine different types of reach-to-grasp actions. Our results support DS, suggesting that the best action representation is based on a relatively large set of synergies, each involving a reduced number of degrees-of-freedom, and that distinct sets of synergies may be involved in distinct tasks.

Details

Title
Evidence for sparse synergies in grasping actions
Author
Prevete, Roberto 1 ; Donnarumma, Francesco 2   VIAFID ORCID Logo  ; Andrea d’Avella 3 ; Pezzulo, Giovanni 2 

 Department of Electric Engineering and Information Technologies (DIETI) Università di Napoli Federico II, Naples, Italy 
 Institute of Cognitive Sciences and Technologies, National Research Council (ISTC-CNR), Rome, Italy 
 Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy; Laboratory of Neuromotor Physiology, Santa Lucia Foundation, Rome, Italy 
Pages
1-16
Publication year
2018
Publication date
Jan 2018
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1986974042
Copyright
© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.