Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements

Crevecoeur, Frédéric; McIntyre, Joseph; Thonnard, Jean-Louis; Lefèvre, Philippe

doi:10.1152/jn.00061.2014

Cited by 11 publications

(7 citation statements)

References 39 publications

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“…Gravity is a defining force that governs the evolution of mechanical forms (Volkmann and Baluška, 2006), shapes and anchors our perception of the environment (Dichgans et al, 1972; Coppola et al, 1998a; Merfeld et al, 1999; Laurens and Angelaki, 2011; Rosenberg and Angelaki, 2014), and imposes fundamental constraints on how we interact with the world (Gaveau et al, 2011, 2014, 2016; Crevecoeur et al, 2014). Humans are unique in having evolved a vertical, bipedal posture that confers benefits such as freeing our hands to interact with objects, elevating our line of sight, and enabling metabolically efficient walking (Alexander, 2004).…”

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confidence: 99%

Gravity estimation and verticality perception

Dakin

Rosenberg

2018

Handbook of Clinical Neurology

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Gravity is a defining force that governs the evolution of mechanical forms, shapes and anchors our perception of the environment, and imposes fundamental constraints on our interactions with the world. Within the animal kingdom, humans are relatively unique in having evolved a vertical, bipedal posture. Although a vertical posture confers numerous benefits, it also renders us less stable than quadrupeds, increasing susceptibility to falls. The ability to accurately and precisely estimate our orientation relative to gravity is therefore of utmost importance. Here we review sensory information and computational processes underlying gravity estimation and verticality perception. Central to gravity estimation and verticality perception is multisensory cue combination, which serves to improve the precision of perception and resolve ambiguities in sensory representations by combining information from across the visual, vestibular, and somatosensory systems. We additionally review experimental paradigms for evaluating verticality perception, and discuss how particular disorders affect the perception of upright. Together, the work reviewed here highlights the critical role of multisensory cue combination in gravity estimation, verticality perception, and creating stable gravity-centered representations of our environment.

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confidence: 99%

Gravity estimation and verticality perception

Dakin

Rosenberg

2018

Handbook of Clinical Neurology

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“…A mismatch between actual and predicted arm inertia, in particular its anisotropy, is another possible explanation. Some of the above findings (Flanagan and Lolley, 2001; Gentili et al, 2004; Crevecoeur et al, 2014) suggest that the anisotropy of arm inertia is accurately accounted for in movement execution. Other studies—Gordon et al (1994a) and ours—point at systematic errors in estimating arm inertia.…”

Section: Discussionmentioning

confidence: 95%

Effect of Position- and Velocity-Dependent Forces on Reaching Movements at Different Speeds

Summa

Casadio

Sanguineti

2016

Front. Hum. Neurosci.

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The speed of voluntary movements is determined by the conflicting needs of maximizing accuracy and minimizing mechanical effort. Dynamic perturbations, e.g., force fields, may be used to manipulate movements in order to investigate these mechanisms. Here, we focus on how the presence of position- and velocity-dependent force fields affects the relation between speed and accuracy during hand reaching movements. Participants were instructed to perform reaching movements under visual control in two directions, corresponding to either low or high arm inertia. The subjects were required to maintain four different movement durations (very slow, slow, fast, very fast). The experimental protocol included three phases: (i) familiarization—the robot generated no force; (ii) force field—the robot generated a force; and (iii) after-effect—again, no force. Participants were randomly assigned to four groups, depending on the type of force that was applied during the “force field” phase. The robot was programmed to generate position-dependent forces—with positive (K+) or negative stiffness (K−)—or velocity-dependent forces, with either positive (B+) or negative viscosity (B−). We focused on path curvature, smoothness, and endpoint error; in the latter we distinguished between bias and variability components. Movements in the high-inertia direction are smoother and less curved; smoothness also increases with movement speed. Endpoint bias and variability are greater in, respectively, the high and low inertia directions. A robust dependence on movement speed was only observed in the longitudinal components of both bias and variability. The strongest and more consistent effects of perturbation were observed with negative viscosity (B−), which resulted in increased variability during force field adaptation and in a reduction of the endpoint bias, which was retained in the subsequent after-effect phase. These findings confirm that training with negative viscosity produces lasting effects in movement accuracy at all speeds.

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“…Previous reports in the literature on this subject are conflicting. Some studies reported a tendency for movement slowing for both vertical and horizontal pointing movements performed in space 58 – 60 or parabolic flight 36 , 61 , 62 . In particular, Mechtcheriakov et al 59 reported significant slowing of aiming arm movements over the initial in-flight sessions and a tendency to have movement durations comparable to pre-flight sessions in later sessions (about 50 days after launch).…”

Section: Discussionmentioning

confidence: 99%

Mental imagery of object motion in weightlessness

2021

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Mental imagery represents a potential countermeasure for sensorimotor and cognitive dysfunctions due to spaceflight. It might help train people to deal with conditions unique to spaceflight. Thus, dynamic interactions with the inertial motion of weightless objects are only experienced in weightlessness but can be simulated on Earth using mental imagery. Such training might overcome the problem of calibrating fine-grained hand forces and estimating the spatiotemporal parameters of the resulting object motion. Here, a group of astronauts grasped an imaginary ball, threw it against the ceiling or the front wall, and caught it after the bounce, during pre-flight, in-flight, and post-flight experiments. They varied the throwing speed across trials and imagined that the ball moved under Earth’s gravity or weightlessness. We found that the astronauts were able to reproduce qualitative differences between inertial and gravitational motion already on ground, and further adapted their behavior during spaceflight. Thus, they adjusted the throwing speed and the catching time, equivalent to the duration of virtual ball motion, as a function of the imaginary 0 g condition versus the imaginary 1 g condition. Arm kinematics of the frontal throws further revealed a differential processing of imagined gravity level in terms of the spatial features of the arm and virtual ball trajectories. We suggest that protocols of this kind may facilitate sensorimotor adaptation and help tuning vestibular plasticity in-flight, since mental imagery of gravitational motion is known to engage the vestibular cortex.

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Gravity-dependent estimates of object mass underlie the generation of motor commands for horizontal limb movements

Cited by 11 publications

References 39 publications

Gravity estimation and verticality perception

Gravity estimation and verticality perception

Effect of Position- and Velocity-Dependent Forces on Reaching Movements at Different Speeds

Mental imagery of object motion in weightlessness

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