A review of grasping as the movements of digits in space

Research output: Contribution to JournalArticleAcademicpeer-review

73 Downloads (Pure)

Abstract

It is tempting to describe human reach-to-grasp movements in terms of two, more or less independent visuomotor channels, one relating hand transport to the object's location and the other relating grip aperture to the object's size. Our review of experimental work questions this framework for reasons that go beyond noting the dependence between the two channels. Both the lack of effect of size illusions on grip aperture and the finding that the variability in grip aperture does not depend on the object's size indicate that size information is not used to control grip aperture. An alternative is to describe grip formation as emerging from controlling the movements of the digits in space. Each digit's trajectory when grasping an object is remarkably similar to its trajectory when moving to tap the same position on its own. The similarity is also evident in the fast responses when the object is displaced. This review develops a new description of the speed-accuracy trade-off for multiple effectors that is applied to grasping. The most direct support for the digit-in-space framework is that prism-induced adaptation of each digit's tapping movements transfers to that digit's movements when grasping, leading to changes in grip aperture for adaptation in opposite directions for the two digits. We conclude that although grip aperture and hand transport are convenient variables to describe grasping, treating grasping as movements of the digits in space is a more suitable basis for understanding the neural control of grasping.

Original languageEnglish
Pages (from-to)1578-1597
Number of pages20
JournalJournal of neurophysiology
Volume122
Issue number4
Early online date24 Jul 2019
DOIs
Publication statusPublished - 30 Sep 2019

Keywords

  • coordination
  • index finger
  • motor
  • prehension
  • thumb

Fingerprint Dive into the research topics of 'A review of grasping as the movements of digits in space'. Together they form a unique fingerprint.

Cite this