Information and force level interact in regulating force output during two and three digit grip configurations

Jacob J Sosnoff, Kimberlee Jordan, Karl M. Newell

Research output: Contribution to journalArticlepeer-review

Abstract

The experiment examined the force fluctuations during two and three digit grip configurations to investigate the relationship between task performance and inter-digit individuation as a function of force level and visual information intermittency rate over ∼100-fold range (0.21-20 Hz). Subjects grasped an object with either the index finger (two digit grip) or the index and middle finger (three digit grip) opposing the thumb and produced isometric force to match a low and high total force level target. Force accuracy was lower at the large visual intermittency conditions and the higher force level. The force variability was lower in the three digit grip. Inter-digit individuation increased as a function of visual intermittency rate and was greater at the low force level. There was no improvement in performance or inter-digit individuation when visual feedback intermittency was greater than ∼6 Hz (∼150 ms). Linear regression between the measures of task performance and inter-digit individuation yielded a significant negative relationship that was only present in the two digit grip when visual feedback rate was 1.67 Hz or lower and in the three digit grip when the feedback rate was 10 Hz or lower. The greater biomechanical degrees of freedom in the three digit grip configuration enable the subject to use, more effectively, visual information feedback at faster timescales in maximizing task performance by increasing digit independence. The shift from visual to nonvisual dominated motor control processes is dependent on the interaction of informational and biomechanical degrees of freedom.

Original languageEnglish (US)
Pages (from-to)76-85
Number of pages10
JournalExperimental Brain Research
Volume167
Issue number1
DOIs
StatePublished - Nov 1 2005
Externally publishedYes

Keywords

  • Digit individuation
  • Grip configuration
  • Visual motor processing

ASJC Scopus subject areas

  • Neuroscience(all)

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