Grasping in absence of feedback: systematic biases endure extensive training

Chiara Bozzacchi, Robert Volcic, Fulvio Domini

Research output: Contribution to journalArticle

Abstract

Reach-to-grasp movements performed without visual and haptic feedback of the hand are subject to systematic inaccuracies. Grasps directed at an object specified by binocular information usually end at the wrong distance with an incorrect final grip aperture. More specifically, moving the target object away from the observer leads to increasingly larger undershoots and smaller grip apertures. These systematic biases suggest that the visuomotor mapping is based on inaccurate estimates of an object’s egocentric distance and 3D structure that compress the visual space. Here we ask whether the appropriate visuomotor mapping can be learned through an extensive exposure to trials where haptic and visual feedback of the hand is provided. By intermixing feedback trials with test trials without feedback, we aimed at maximizing the likelihood that the motor execution of test trials is positively influenced by that of preceding feedback trials. We found that the intermittent presence of feedback trials both (1) largely reduced the positioning error of the hand with respect to the object and (2) affected the shaping of the hand before the final grasp, leading to an overall more accurate performance. While this demonstrates an effective transfer of information from feedback trials to test trials, the remaining biases indicate that a compression of visual space is still taking place. The correct visuomotor mapping, therefore, could not be learned. We speculate that an accurate reconstruction of the scene at movement onset may not actually be needed. Instead, the online monitoring of the hand position relative to the object and the final contact with the object are sufficient for a successful execution of a grasp.

Original languageEnglish (US)
Pages (from-to)255-265
Number of pages11
JournalExperimental Brain Research
Volume234
Issue number1
DOIs
StatePublished - Jan 1 2016

Fingerprint

Hand Strength
Hand
Sensory Feedback

Keywords

  • Calibration
  • Grasping
  • Haptic feedback
  • Visual feedback
  • Visuomotor learning

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Grasping in absence of feedback : systematic biases endure extensive training. / Bozzacchi, Chiara; Volcic, Robert; Domini, Fulvio.

In: Experimental Brain Research, Vol. 234, No. 1, 01.01.2016, p. 255-265.

Research output: Contribution to journalArticle

Bozzacchi, Chiara ; Volcic, Robert ; Domini, Fulvio. / Grasping in absence of feedback : systematic biases endure extensive training. In: Experimental Brain Research. 2016 ; Vol. 234, No. 1. pp. 255-265.
@article{39492615f3c14195ad0965e790e3eac8,
title = "Grasping in absence of feedback: systematic biases endure extensive training",
abstract = "Reach-to-grasp movements performed without visual and haptic feedback of the hand are subject to systematic inaccuracies. Grasps directed at an object specified by binocular information usually end at the wrong distance with an incorrect final grip aperture. More specifically, moving the target object away from the observer leads to increasingly larger undershoots and smaller grip apertures. These systematic biases suggest that the visuomotor mapping is based on inaccurate estimates of an object’s egocentric distance and 3D structure that compress the visual space. Here we ask whether the appropriate visuomotor mapping can be learned through an extensive exposure to trials where haptic and visual feedback of the hand is provided. By intermixing feedback trials with test trials without feedback, we aimed at maximizing the likelihood that the motor execution of test trials is positively influenced by that of preceding feedback trials. We found that the intermittent presence of feedback trials both (1) largely reduced the positioning error of the hand with respect to the object and (2) affected the shaping of the hand before the final grasp, leading to an overall more accurate performance. While this demonstrates an effective transfer of information from feedback trials to test trials, the remaining biases indicate that a compression of visual space is still taking place. The correct visuomotor mapping, therefore, could not be learned. We speculate that an accurate reconstruction of the scene at movement onset may not actually be needed. Instead, the online monitoring of the hand position relative to the object and the final contact with the object are sufficient for a successful execution of a grasp.",
keywords = "Calibration, Grasping, Haptic feedback, Visual feedback, Visuomotor learning",
author = "Chiara Bozzacchi and Robert Volcic and Fulvio Domini",
year = "2016",
month = "1",
day = "1",
doi = "10.1007/s00221-015-4456-9",
language = "English (US)",
volume = "234",
pages = "255--265",
journal = "Experimental Brain Research",
issn = "0014-4819",
publisher = "Springer Verlag",
number = "1",

}

TY - JOUR

T1 - Grasping in absence of feedback

T2 - systematic biases endure extensive training

AU - Bozzacchi, Chiara

AU - Volcic, Robert

AU - Domini, Fulvio

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Reach-to-grasp movements performed without visual and haptic feedback of the hand are subject to systematic inaccuracies. Grasps directed at an object specified by binocular information usually end at the wrong distance with an incorrect final grip aperture. More specifically, moving the target object away from the observer leads to increasingly larger undershoots and smaller grip apertures. These systematic biases suggest that the visuomotor mapping is based on inaccurate estimates of an object’s egocentric distance and 3D structure that compress the visual space. Here we ask whether the appropriate visuomotor mapping can be learned through an extensive exposure to trials where haptic and visual feedback of the hand is provided. By intermixing feedback trials with test trials without feedback, we aimed at maximizing the likelihood that the motor execution of test trials is positively influenced by that of preceding feedback trials. We found that the intermittent presence of feedback trials both (1) largely reduced the positioning error of the hand with respect to the object and (2) affected the shaping of the hand before the final grasp, leading to an overall more accurate performance. While this demonstrates an effective transfer of information from feedback trials to test trials, the remaining biases indicate that a compression of visual space is still taking place. The correct visuomotor mapping, therefore, could not be learned. We speculate that an accurate reconstruction of the scene at movement onset may not actually be needed. Instead, the online monitoring of the hand position relative to the object and the final contact with the object are sufficient for a successful execution of a grasp.

AB - Reach-to-grasp movements performed without visual and haptic feedback of the hand are subject to systematic inaccuracies. Grasps directed at an object specified by binocular information usually end at the wrong distance with an incorrect final grip aperture. More specifically, moving the target object away from the observer leads to increasingly larger undershoots and smaller grip apertures. These systematic biases suggest that the visuomotor mapping is based on inaccurate estimates of an object’s egocentric distance and 3D structure that compress the visual space. Here we ask whether the appropriate visuomotor mapping can be learned through an extensive exposure to trials where haptic and visual feedback of the hand is provided. By intermixing feedback trials with test trials without feedback, we aimed at maximizing the likelihood that the motor execution of test trials is positively influenced by that of preceding feedback trials. We found that the intermittent presence of feedback trials both (1) largely reduced the positioning error of the hand with respect to the object and (2) affected the shaping of the hand before the final grasp, leading to an overall more accurate performance. While this demonstrates an effective transfer of information from feedback trials to test trials, the remaining biases indicate that a compression of visual space is still taking place. The correct visuomotor mapping, therefore, could not be learned. We speculate that an accurate reconstruction of the scene at movement onset may not actually be needed. Instead, the online monitoring of the hand position relative to the object and the final contact with the object are sufficient for a successful execution of a grasp.

KW - Calibration

KW - Grasping

KW - Haptic feedback

KW - Visual feedback

KW - Visuomotor learning

UR - http://www.scopus.com/inward/record.url?scp=84954392875&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84954392875&partnerID=8YFLogxK

U2 - 10.1007/s00221-015-4456-9

DO - 10.1007/s00221-015-4456-9

M3 - Article

C2 - 26449965

AN - SCOPUS:84954392875

VL - 234

SP - 255

EP - 265

JO - Experimental Brain Research

JF - Experimental Brain Research

SN - 0014-4819

IS - 1

ER -