Biological Cybernetics

, Volume 102, Issue 1, pp 45–55

A neural mechanism of synergy formation for whole body reaching

  • Pietro Morasso
  • Maura Casadio
  • Vishwanathan Mohan
  • Jacopo Zenzeri
Original Paper

DOI: 10.1007/s00422-009-0349-y

Cite this article as:
Morasso, P., Casadio, M., Mohan, V. et al. Biol Cybern (2010) 102: 45. doi:10.1007/s00422-009-0349-y

Abstract

The present study proposes a computational model for the formation of whole body reaching synergy, i.e., coordinated movements of lower and upper limbs, characterized by a focal component (the hand must reach a target) and a postural component (the center of mass must remain inside the support base). The model is based on an extension of the equilibrium point hypothesis that has been called Passive Motion Paradigm (PMP), modified in order to achieve terminal attractor features and allow the integration of multiple constraints. The model is a network with terminal attractor dynamics. By simulating it in various conditions it was possible to show that it exhibits many of the spatio-temporal features found in experimental data. In particular, the motion of the center of mass appears to be synchronized with the motion of the hand and with proportional amplitude. Moreover, the joint rotation patterns can be accounted for by a single functional degree of freedom, as shown by principal component analysis. It is also suggested that recent findings in motor imagery support the idea that the PMP network may represent the motor cognitive part of synergy formation, uncontaminated by the effect of execution.

Keywords

Whole body reaching Equilibrium point hypothesis Passive motion paradigm Synergy formation 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Pietro Morasso
    • 1
    • 2
    • 3
  • Maura Casadio
    • 1
    • 2
  • Vishwanathan Mohan
    • 1
  • Jacopo Zenzeri
    • 1
    • 2
  1. 1.Department of Robotics, Brain and Cognitive SciencesItalian Institute of TechnologyGenoaItaly
  2. 2.Department of Informatics, Systems, Telecommunications (DIST)University of GenoaGenoaItaly
  3. 3.National Institute of NeuroscienceTurinItaly

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