Control of finger force vectors with changes in fingertip referent coordinates

Yen Hsun Wu, Vladimir M. Zatsiorsky, Mark Latash

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

The central hypothesis explored in the experiment is that adjustments of fingertip force vectors during object manipulation could result from a simple scaling rule applied to commands to individual digits. The commands have been associated with referent coordinates of the digit tips. The subjects performed quick lifting movements (over 20 cm in under 0.5 s) of a horizontally oriented handle with different combinations of the external load and torque. The prismatic grasp was used with the 4 fingers pressing on the bottom of the handle and the thumb acting on its top. Principal component and correlation analyses applied to the normal and tangential force vector components confirmed that the force direction of each digit was kept nearly constant in the object-centered referent frame across the loading conditions and movement phases. The middle and ring fingers showed weaker correlations between the force components as compared to the index and little fingers. The differences were likely related to the different roles of the normal force components in the moment of force production. The neural control of the hand, within the studied task, may be adequately described as a simple rule applied to a handful of parameters, such as the referent digit-tip coordinates.

Original languageEnglish (US)
Pages (from-to)15-20
Number of pages6
JournalJournal of motor behavior
Volume45
Issue number1
DOIs
StatePublished - Jan 1 2013

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Orthopedics and Sports Medicine
  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience

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