Delayed Visual Feedback Affects Both Manual Tracking and Grip Force Control When Transporting a Handheld Object

2010 ◽  
Vol 104 (2) ◽  
pp. 641-653 ◽  
Author(s):  
Fabrice R. Sarlegna ◽  
Gabriel Baud-Bovy ◽  
Frédéric Danion
Keyword(s):  
Visual Feedback ◽  
Grip Force ◽  
Task Complexity ◽  
Dynamic Properties ◽  
Internal Representation ◽  
Object Motion ◽  
Load Force ◽  
Manual Tracking ◽  
Actual Object ◽  
Delayed Visual Feedback

When we manipulate an object, grip force is adjusted in anticipation of the mechanical consequences of hand motion (i.e., load force) to prevent the object from slipping. This predictive behavior is assumed to rely on an internal representation of the object dynamic properties, which would be elaborated via visual information before the object is grasped and via somatosensory feedback once the object is grasped. Here we examined this view by investigating the effect of delayed visual feedback during dextrous object manipulation. Adult participants manually tracked a sinusoidal target by oscillating a handheld object whose current position was displayed as a cursor on a screen along with the visual target. A delay was introduced between actual object displacement and cursor motion. This delay was linearly increased (from 0 to 300 ms) and decreased within 2-min trials. As previously reported, delayed visual feedback altered performance in manual tracking. Importantly, although the physical properties of the object remained unchanged, delayed visual feedback altered the timing of grip force relative to load force by about 50 ms. Additional experiments showed that this effect was not due to task complexity nor to manual tracking. A model inspired by the behavior of mass-spring systems suggests that delayed visual feedback may have biased the representation of object dynamics. Overall, our findings support the idea that visual feedback of object motion can influence the predictive control of grip force even when the object is grasped.

scholarly journals Force feedback delay affects perception of stiffness but not action, and the effect depends on the hand used but not on the handedness

2018 ◽  
Vol 120 (2) ◽  
pp. 781-794 ◽  
Author(s):  
Raz Leib ◽  
Inbar Rubin ◽  
Ilana Nisky
Keyword(s):  
Force Field ◽  
Grip Force ◽  
Force Feedback ◽  
Internal Representation ◽  
Elastic Force ◽  
Perceptual Bias ◽  
Load Force ◽  
Test Case ◽  
Robotic Device ◽  
Left Handed

Interaction with an object often requires the estimation of its mechanical properties. We examined whether the hand that is used to interact with the object and their handedness affected people’s estimation of these properties using stiffness estimation as a test case. We recorded participants’ responses on a stiffness discrimination of a virtual elastic force field and the grip force applied on the robotic device during the interaction. In half of the trials, the robotic device delayed the participants’ force feedback. Consistent with previous studies, delayed force feedback biased the perceived stiffness of the force field. Interestingly, in both left-handed and right-handed participants, for the delayed force field, there was even less perceived stiffness when participants used their left hand than their right hand. This result supports the idea that haptic processing is affected by laterality in the brain, not by handedness. Consistent with previous studies, participants adjusted their applied grip force according to the correct size and timing of the load force regardless of the hand that was used, the handedness, or the delay. This suggests that in all of these conditions, participants were able to form an accurate internal representation of the anticipated trajectory of the load force (size and timing) and that this representation was used for accurate control of grip force independently of the perceptual bias. Thus these results provide additional evidence for the dissociation between action and perception in the processing of delayed information. NEW & NOTEWORTHY Introducing delay to force feedback during interaction with an elastic force field biases the perceived stiffness of the force field. We show that this bias depends on the hand that was used for probing but not on handedness. At the same time, both left-handed and right-handed participants adjusted their applied grip force while using either their left or right hands in anticipation of the correct magnitude and timing despite the delay in load force.

Grip Force-Load Force Coupling Is Influenced by Altered Visual Feedback about Object Kinematics

2019 ◽  
Vol 52 (5) ◽  
pp. 612-624 ◽  
Author(s):  
Francis M. Grover ◽  
Sarah M. Schwab ◽  
Michael A. Riley
Keyword(s):  
Visual Feedback ◽  
Grip Force ◽  
Load Force ◽  
Force Load ◽  
Force Coupling

scholarly journals Adaptation and compensation for somatosensory deficits in object handling: evidence from a patient with large fibre sensory neuropathy

2021 ◽  
Author(s):  
Ross Parry ◽  
Fabrice R Sarlegna ◽  
Nathanaël Jarrassé ◽  
Agnes Roby-Brami
Keyword(s):  
Visual Feedback ◽  
Grip Force ◽  
Sensory Neuropathy ◽  
External Perturbation ◽  
Maximum Load ◽  
Object Orientation ◽  
Temporal Organization ◽  
Load Force ◽  
Compensatory Mechanisms ◽  
Large Fibre

The purpose of this study was to determine the contributions of feedforward and feedback processes on grip force regulation and object orientation during functional manipulation tasks. One patient with massive somatosensory loss resulting from large fibre sensory neuropathy, and ten control participants were recruited. Three experiments were conducted: 1) perturbation to static holding; 2) discrete vertical movement; and 3) functional grasp and place. The availability of visual feedback was also manipulated to assess the nature of compensatory mechanisms. Results from experiment 1 indicated that both the deafferented patient and controls used anticipatory grip force adjustments prior to self-induced perturbation to static holding. The patient exhibited increased grip response time, but the magnitude of grip force adjustments remained correlated with perturbation forces in the self-induced and external perturbation conditions. In experiment 2, the patient applied peak grip force substantially in advance of maximum load force. Unlike controls, the patient's ability to regulate object orientation was impaired without visual feedback. In experiment 3, the duration of unloading, transport and release phases were longer for the patient, with increased deviation of object orientation at phase transitions. These findings show that the deafferented patient uses distinct modes of anticipatory control according to task constraints, and that responses to perturbations are mediated by alternative afferent information. The loss of somatosensory feedback thus appears to impair control of object orientation, while variation in the temporal organization of functional tasks may reflect strategies to mitigate object instability associated with changes in movement dynamics.

scholarly journals The effect of force feedback delay on stiffness perception and grip force modulation during tool-mediated interaction with elastic force fields

2015 ◽  
Vol 113 (9) ◽  
pp. 3076-3089 ◽  
Author(s):  
Raz Leib ◽  
Amir Karniel ◽  
Ilana Nisky
Keyword(s):  
Grip Force ◽  
Force Feedback ◽  
Force Fields ◽  
Precision Grip ◽  
Internal Representation ◽  
Force Sensor ◽  
Elastic Force ◽  
Load Force ◽  
Perceptual Task ◽  
Virtual Force

During interaction with objects, we form an internal representation of their mechanical properties. This representation is used for perception and for guiding actions, such as in precision grip, where grip force is modulated with the predicted load forces. In this study, we explored the relationship between grip force adjustment and perception of stiffness during interaction with linear elastic force fields. In a forced-choice paradigm, participants probed pairs of virtual force fields while grasping a force sensor that was attached to a haptic device. For each pair, they were asked which field had higher level of stiffness. In half of the pairs, the force feedback of one of the fields was delayed. Participants underestimated the stiffness of the delayed field relatively to the nondelayed, but their grip force characteristics were similar in both conditions. We analyzed the magnitude of the grip force and the lag between the grip force and the load force in the exploratory probing movements within each trial. Right before answering which force field had higher level of stiffness, both magnitude and lag were similar between delayed and nondelayed force fields. These results suggest that an accurate internal representation of environment stiffness and time delay was used for adjusting the grip force. However, this representation did not help in eliminating the bias in stiffness perception. We argue that during performance of a perceptual task that is based on proprioceptive feedback, separate neural mechanisms are responsible for perception and action-related computations in the brain.

scholarly journals Better grip force control by attending to the controlled object: Evidence for direct force estimation from visual motion

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shinya Takamuku ◽  
Hiroaki Gomi
Keyword(s):  
Visual Feedback ◽  
Force Control ◽  
Grip Force ◽  
Visual Motion ◽  
Inverse Dynamics ◽  
Object Motion ◽  
Hand Position ◽  
Force Estimation ◽  
Grip Force Control ◽  
Dynamic Forces

Abstract Estimating forces acting between our hand and objects is essential for dexterous motor control. An earlier study suggested that vision contributes to the estimation by demonstrating changes in grip force pattern caused by delayed visual feedback. However, two possible vision-based force estimation processes, one based on hand position and another based on object motion, were both able to explain the effect. Here, to test each process, we examined how visual feedback of hand and object each contribute to grip force control during moving an object (mass) connected to the grip by a damped-spring. Although force applied to the hand could be estimated from its displacement, we did not find any improvements by the hand feedback. In contrast, we found that visual feedback of object motion significantly improved the synchrony between grip and load forces. Furthermore, when both feedback sources were provided, the improvement was observed only when participants were instructed to direct their attention to the object. Our results suggest that visual feedback of object motion contributes to estimation of dynamic forces involved in our actions by means of inverse dynamics computation, i.e., the estimation of force from motion, and that visual attention directed towards the object facilitates this effect.

scholarly journals Stretching the skin immediately enhances perceived stiffness and gradually enhances the predictive control of grip force

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Mor Farajian ◽  
Raz Leib ◽  
Hanna Kossowsky ◽  
Tomer Zaidenberg ◽  
Ferdinando A Mussa-Ivaldi ◽  
...  
Keyword(s):  
Predictive Control ◽  
Sensory Processing ◽  
Grip Force ◽  
Perception And Action ◽  
Internal Representation ◽  
Load Force ◽  
Behavioral Study ◽  
Tactile Information ◽  
Gradual Development ◽  
Kinesthetic Information

When manipulating objects, we use kinesthetic and tactile information to form an internal representation of their mechanical properties for cognitive perception and for preventing their slippage using predictive control of grip force. A major challenge in understanding the dissociable contributions of tactile and kinesthetic information to perception and action is the natural coupling between them. Unlike previous studies that addressed this question either by focusing on impaired sensory processing in patients or using local anesthesia, we used a behavioral study with a programmable mechatronic device that stretches the skin of the fingertips to address this issue in the intact sensorimotor system. We found that artificial skin-stretch increases the predictive grip force modulation in anticipation of the load force. Moreover, the stretch causes an immediate illusion of touching a harder object that does not depend on the gradual development of the predictive modulation of grip force.

Sensorimotor Mapping for Anticipatory Grip Force Modulation

2010 ◽  
Vol 104 (3) ◽  
pp. 1401-1408 ◽  
Author(s):  
Frédéric Crevecoeur ◽  
Jean-Louis Thonnard ◽  
Philippe Lefèvre
Keyword(s):  
Grip Force ◽  
Experimental Studies ◽  
Internal Representation ◽  
Load Force ◽  
Voluntary Movements ◽  
Discrete Point ◽  
Movement Kinematics ◽  
Force Modulation ◽  
Point To Point ◽  
The Relationship

During object manipulation, predictive grip force modulation allows compensation for inertial forces induced by the object's acceleration. This coupling between grip force (GF) and load force (LF) during voluntary movements has demonstrated high levels of complexity, adaptability, and flexibility under many loading conditions in a broad range of experimental studies. The association between GF and LF indicates the presence of internal models underlying predictive GF control. The present experiment sought to identify the variables taken into account during GF modulation at the initiation of a movement. Twenty subjects performed discrete point-to-point movements under normal and hypergravity conditions induced by parabolic flights. Two control experiments performed under normal gravitational conditions compared the observed effect of the increase in gravity with the effects of a change in movement kinematics and a change in mass. In hypergravity, subjects responded accurately to the increase in weight during stationary holding but overestimated inertial loads. During dynamic phases, the relationship between GF and LF under hypergravity varied in a manner similar to the control test in which object mass was increased, whereas a change in movement kinematics could not reproduce this result. We suggest that the subjects' strategy for anticipatory GF modulation is based on sensorimotor mapping that combines the perception of the weight encoded during stationary holding with an internal representation of the movement kinematics. In particular, such a combination reflects a prior knowledge of the unequivocal relationship linking mass, weight, and loads under the invariant gravitational context experienced on Earth.

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